GMG Fixes a Blown Oil Pump in a MEP003A – The Benefits of Our Warranty Program


GMG recently fixed a blown oil pump in a customer’s MEP003A. Bad things can happen, even though we refurbish and load-bank a unit. Under our exclusive warranty program, we covered this repair. Typically, we only cover parts (not labor) in any warranty situation, but we made an exception and covered labor costs, which were over $600! We stand behind our units and our warranty and believe our warranty is the best (and only) one in the business. Who else warrants a machine manufactured over 30 years old?!

Here are some of the pictures of the damaged oil pump for your reference. The symptoms of this failure were:

  • No oil pressure was registering on the gauge (this is often a bad gauge situation, but not this time).
  • Unit would shut down (correctly) due to low oil pressure, thus protecting the rest of the engine and mechanicals.


  • MEP003A-MEP002A-Blown-Oil-Pump-Gears-6 MEP003A-MEP002A-Blown-Oil-Pump-Gears-5 MEP003A-MEP002A-Blown-Oil-Pump-Gears-4 MEP003A-MEP002A-Blown-Oil-Pump-Gears-3


So how do the MEP002A and MEP802A compare for noise? Listen for yourself

We get this question a lot:  So how to MEP002A units compare to their new generation counterpart in terms of sound level? The former doesn’t have a sound kit (ASK = Acoustic Suppression Kit) and the latter does. Listen for yourself. It is a material difference, but the MEP002A is not nearly as loud as some make it out to be. The water-cooled MEP802A with sound kit definitely quiets the unit down especially at the higher frequencies.


My Generator Starts When Cold, But Not When Hot!


We live in a crazy world! I thought warm diesel engines should start easier than cold ones?! “My Generator Starts When Cold, But Not When Hot!” That is a true statement and remains true. The problem might not lie in the engine itself or the injectors or the injection pump or anything related to the engine specifically. It could lie in a supporting system.

Fuel, air, compression…the holy trinity of old-school diesels. Never forget it! Air is easy to check, so do it first. Make sure you have a clean filter.

Compression is easy to. Next time you get the generator running, crack each of your injection lines, just BEFORE they attach to each injector. If you have good compression and a good injector, every time you do this, the engine should noticeably loose some oomph and you should hear an audible difference. Do this for every injector. If you do this and you hear no change, chances are the injector could be failing or the compression in that cylinder could be terrible (e.g. broken ring, broken rod, etc.). Hopefully it is just a bad injector. If you keep a spare injector on hand, you can swap out injectors to test and try the same procedure. If that doesn’t work, you’re looking at a rebuild of some sort for at least that cylinder…

Now that compression and air have been ruled out (hopefully)…we are left with the usual suspect…fuel…So why would it start cold, but not hot? Does not seem intuitive. The easiest thing to test is to ensure a clean fuel system leading up to the injection pump. Injection pumps rarely work intermittently…They either work or don’t.  If they don’t they could be seized.  But in our scenario, the engine does work, when cold! So we know the pump is most likely good and the injectors are good enough.

On the MEP002A and MEP003A and on many diesel generators, there are lift pumps. On these units, they are facet fuel pumps 24v.  On these units the government installed 3 of them! Pretty nice as one is for aux fuel only. The other two are in series and only one must work to operate. Ensure:

  • Fuel tank is clean
  • ALL fuel lines have been blown out with compressed air
  • ALL filters are clean

Now check each of the two in-series 24v fuel pumps (also check the aux one eventually)…You can twist the bottom off of each one and check for crud build-up. There is a gasket and screen in each of these acting as a crude filter. If these units burned crude oil with thinner, there could be varnish and crud build-up that blocks these screens. If you need new screens for the MEP002A or MEP003A fuel pumps go here. If you’re lucky, you’ll see crud and hopefully be on your way to a successful and easy repair.  Tell us what you think and how things went. Any helpful hints can help others.

Wiring Diagrams for MEP002A & MEP003A Military Diesel Generators


We have had requests for diagrams for the MEP002A and MEP003A wiring.  In this post you will find 3 high resolution photos of a new Control Box that we have in stock (yes, it’s for sale;-). Hope this helps you with your electrical needs.

Can I Run My 120/240V Wired House With A 120/208V Three Phase Generator?

Below is a great video that concerns itself with answering this oft-asked question. Many military generators are only configured to output three phase electricity, especially the larger units including the MEP004A, MEP005a and up.  Note that the MEP002A and MEP003A models output single phase 120/240V single phase power just fine and are not the focus of this post (That is the main reason we focus on those units.)

So the short answer to this question is, YES!  The medium answer is YES, BUT!  The long answer is the following:

Single phase power that typically comes to a home has two hot legs of 120v each.  You can use either leg to power 120v devices or combine both hot legs to power a 240v appliance or motor (e.g. for a well-pump).  This power is all 60Hz.

Three phase power has three hot legs, each of 120v.  You can use any one hot leg to power 120v devices exactly the way you do with single phase power.  So you would typically have four wires coming to your home with three hot and one neutral.  In the more typical single phase scenario, you would have three wires coming to your home, two hot and one neutral.  In either case any one of these legs gets you 120v power so any and all devices that run on 120v power will be fine. This includes all devices plugged into your standard 120v outlet.

Note that in either of the scenarios above, single or three phase, the frequency remains at 60Hz (in the US).

The wrinkle with three phase power comes when you would like to power 240v devices (e.g. a well pump, stove, dryer). If the device’s nameplate states that it can run at 208v (in addition to say 220v or 240v), you are fine.  Sometimes the nameplate will state 208-240v as acceptable voltage ranges.  Most modern devices can support this, but you must check the nameplate of each device to be powered.  So under almost all (typically 90%+) of everything you run in your home or shop will support being run at 208v (which is associated with a three phase generator output).

So what’s the big deal or difference with using a three phase generator output to power your home?  Since a three phase generator has three hot legs and you are only using two of the three to wire to your typical transfer switch or two bus breaker panel, you are only extracting 2/3 of the total potential capacity of the generator.  One hot leg of the generator is simply not used as your home is wired for only two hot legs.  Who cares?! Since generators in general run on fuel (diesel, gas, propane) and a generator running at no load and 100% load consume similar amounts of fuel to stay running at 1800 or 3600 rpm (for 60Hz applications), you are running at 2/3 of efficiency (power output per unit of fuel), which may or may not be of great concern.  Put another way, generators are generating electricity, whether you use it or not, so if you want maximum efficiency (power output per unit of fuel), you want to run at 80-100% depending on the make and model of the generator. For example, most military diesel units like to be run in the 80% capacity range to maintain the ideal engine temperature and operating conditions.  If you only utilize two of three hot legs, you are essentially only using 2/3 of this 80-100% capacity.  Doing the math would be 0.667 x 0.800 = 0.534 or 53% of designed capacity.  So if you have a 30kw generator and it’s configured for three phase and you are only using two of the three hot legs, you would have  revised capacity of 20kw and generally use only 80% of this or 16kw.

So fuel efficiency drops dramatically with the above configuration, but electricity-wise, you can generally run what you need and want to. So, for the occasional use scenario, there is no problem, but the more often you run this configuration, your fuel bills might start climbing! For most of us, fuel is a real cost.  So in the end, the final determination will relate to your application, needs, and desired fuel efficiency.

Watch this great video from You Tube to learn more!


How To Break-In a New Re-manufactured Engine or a New Refurbished Generator from GMG


We get this question A LOT!  Some customers buy new MEP002A or MEP003A re-manufactured engines from GMG. Some buy our refurbished generators complete. In either case, we recommend a Break-In period, especially for re-manufactured engines.  For refurbished generators, we recommend an early oil change in the 50 hour range (vs the normal 100 interval) to ensure that any debris, corrosion, sand, etc. that may have entered or built-up while the unit was sitting for a long time is eliminated from the system.

So for re-manufactured engines, follow this break-in routine:

  1. Use new clean 15W40 oil (no need to use synthetic, but synthetic is fine).  You may also choose a formal break-in oil such as:  Lucas, Amsoil, Royal Purple, or John Deere – they all make break-in oils of 30W.  This weight is better suited to above freezing temperatures, so if you need to break-in your engine in the cold, straight 15W40 is safer.  Either will do. If above freezing, use special break-in oil. Below freezing use 15W40.
  2. It is common to burn oil at first as the rings need to seat on the cylinder walls.  Because of this you should check the oil level EVERY time you use the unit or once every 8 hours of use, whichever comes first. Top off oil as needed.
  3. Do not idle the engine. Run it at 1800 rpm/60Hz ALWAYS.  Same goes for normal use.
  4. Do not baby the unit. You should run it at 1800 rpm/60Hz with a LOAD on it.  Same goes for normal use.
  5. Run for hours (not minutes) at a time, esp. if it is colder outside. These units are rated for continuous use and they should be used for hours. So on your first run, you can run for 2-4 hours straight. Do it again a few times, checking oil level every time.
  6. Change oil and filter after 50 hours of use (This is half the normal interval).
  7. The above assumes that your fuel system has been cleaned out as all of our refurbished units have been.  It also assumes you have a clean air-filter.

For refurbished generators, follow the above, but do not use break-in oil. Simply use 15W40 oil.

Change your oil and filter one time a year or every 100 hours for optimal performance.  Clean/fresh oil is more important than the brand you choose;-)

Comments welcome on all fronts.

We Have Onan Diesel Fuel Injectors In Stock! Onan/Yanmar 147-0136


Is your generator (MEP002A or MEP003A) sputtering?  Is it coughing smoke in a rhythm?  If it is, it could very well be time for new injectors that will improve the performance of your generator dramatically.  We now stock this very difficult to find injector. It was made by Onan in the early days and was then made by Yanmar for Onan. You can purchase Onan 147-0136 Diesel Fuel Injectors here.

Re-energizing Dead Generators

Two methods for field-flashing generators, one using an existing 110 volt source, one using an electric drill – by End Times Report

Home generators in storage can “go flat” or lose their magnetism. Then they will not produce electricity, even though the small gasoline engine turning them is running just fine. There is a simple way to fix that, however. Large generators (like hydro power units) lose their magnetism very quickly: that is the reason Gary North says that if the grid goes down completely for 2 weeks it may well stay down: the power needed to re-energize the generators might not be available. It takes electricity of the correct voltage and frequency to reestablish the magnetism in the generator to produce electricity.

As many people now have generators in storage and may not use them until the “normal” electric grid is well and truly trashed, knowing how to get a generator re-magnetized could be very handy information.

First some basics in electrical connections involving household wiring. (Forget color coding for 12 volt DC systems — that is different, and it is easy to get confused.)

The color coding scheme in AC wiring, stipulated by the National Electrical Code is:

With 110 VAC house wiring, the white wire is neutral, the green wire is “ground,” and the black wire is “hot,” carrying the electricity.

For 220 volt AC wiring, Black and Red should ALWAYS be used as hot wires. White — ALWAYS used as neutral wire. Green (or bare) — ALWAYS the ground wire.

Got that? It is crucial!

Look at an electrical wall socket. The left “eye” is longer than the left — it is the neutral (white) socket; the right “eye” is the hot (black) socket, and the mouth is the round (green) ground socket. Cords which only have 2 wires often have the ground spade larger than the other spade, as they will operate “polarized” appliances. Light bulbs don’t give a darn which way the power flows through the tungsten resistance filament to generate heat (light), but many motors and appliances require the proper flow of electricity (polarity).  And some appliances are grounded to their frame, so reversing the polarity can make the entire appliance “hot” and quite shocking (and life threatening) to touch.

It is important to know the correct arrangement of electrical flow because generators MUST have the correct polarity. When they lose their magnetism they are in a neutral state, so it is entirely possible to energize them in reverse — to reverse their polarity. You don’t want to do that, and it is easy to avoid.

Field Flashing Using a 110 volt Source

To re-energize a generator it must be fed electricity at the correct voltage and cycle rate while it is running. This means power must be available from household power or a borrowed generator. Most generators are 110 VAC 60 cycle, a few are 220 VAC 60 cycle, and some have dual 110 VAC 60 cycle armatures and windings (which when combined produce 220 VAC). But as all of them have 110 VAC receptacles, they can be energized in exactly the same manner.

A device must be built to connect the power source to the dead generator. Each end must have 3 wire male plugs, two wires of 12 to 16 gauge about 6 feet long, and 3 light bulb fixtures are required. The white wire is connected from the right side (holding it) or left side (looking at face) of the male plugs. The positive (black) wire must have 3 light bulb fixtures wired in series, so electricity flows through each light bulb from one end to the other. This is most easily accomplished by installing 3 porcelain light fixtures on a board and connecting them in series, but any expedient method that does not short out the wires may be employed in an emergency. Put 60 watt light bulbs in each fixture.

NOTE:  THE POLARITY IN THE ILLUSTRATION ABOVE IS REVERSED.  The black wire should go into the RIGHT SIDE plug on each end, not the left side as shown.  The white wire goes uninterrupted from the LEFT plug blade to the other end on the LEFT side.

There is no need for a 3rd (green) wire in this arrangement: 3 wire male plugs are used to simplify getting the polarity correct when under duress and pressure, nothing more.

You will remember that wall sockets are “hot” and have female connections, and when you plug in an appliance or cord that all exposed connections disappear or are covered. That is to avoid the hazard of a self-induced hair raising experience known variously as “electric shock therapy” or electrocution. But the device you have just constructed has male plugs at both ends! Obviously caution is mandatory here, and things must be done in the correct sequence. But there is no alternative to this method that I know of, so you simply must be careful, keep the rug rats away, don’t stand in a puddle of water, and tell the spouse to pray instead of scream.

Fire up the engine on the dead generator and warm it up until it runs smoothly with the choke off: it isn’t under load yet, but it will be. Then fire up the borrowed generator. Plug your contraption into the dead generator, then into the spare generator or household current. The three 60 watt bulbs will start flashing: when they are perfectly in sync, carefully pull the plug from the spare generator, then the other generator which has just been re-energized.  DO NOT TOUCH THE EXPOSED ENDS OF THE PLUGS – THEY ARE HOT!

Using a voltage tester, you will find the “dead” generator is now putting out 110 VAC power AT THAT SOCKET. If you have a 220 VAC generator, test the other 110 VAC socket: if it is dead, energize it in the same way as outlined above. Then both 110 volt armatures will be putting out 110 VAC 60 cycle power in sync, and combine to produce 220 VAC as well.

Yes, the system described above works, and works well. Using this technique will enable you to salvage a useless generator at very little cost. And done with care it need not be a hair raising experience — quite handy for those of us lacking same.

Have I done it? You bet. I bought my generator back in 1974 when building a cabin in the woods of Western Oregon (The “back to the land” hippies found us already there!). But in the early 80’s I didn’t use the generator for awhile (got soft), and it lost its magnetism. So I did it, and it works well to the day the engine died in 2004. It simply wasn’t worth rebuilding the engine, as those old engines were designed to run on leaded gasoline.  So I replaced it with a 3,000 watt generator and built a cart to move it around.

There are other uses for short extension cords with male plugs on both ends: they must be home built, used with care (and hidden from OSHA), but they can be very useful. For example, I modified the circuit breaker box on my well pump by adding an extension cord on 12-3 wire to a standard wall socket in a normal outlet box. But I connected the extension cord to the BOTTOM side of the circuit breaker — to the pump wire connection. When the circuit breaker is “on” and power flowing, I can plug in a clamp light with a 150 watt light bulb and prevent the pump from freezing.

But if the power goes out, I can flip the circuit breaker off, thereby isolating the pump from the house wiring. I can fire up the generator, plug one male end into the socket connected to the circuit breaker box, plug in the other male end to the generator, and power the well pump. And I don’t have the fear of electricity flowing backwards past the circuit breaker box and up the line. When I want to turn off the pump, I pull the plug from the generator FIRST.


A reader sent me this link and method.  I have not used this method myself, but it has great applications for the future given that it does NOT require the use of electricity from another source.  Another reader told me he tried it and it worked!

I always give credit where due.  A reader sent me the link, the link is shown, and the information supposedly came from Briggs & Stratton.  Miles

Field Flashing Using an Electric Drill

This tip comes from the Briggs & Stratton Customer Education Department. As an alternative to flashing a rotor winding with a battery applied to the brushes, an electric drill may be used. Follow these steps to flash the generator:

  • Plug the electric drill into the generator receptacle. (Cordless drills do not work)
  • If the drill is reversible, move the direction switch to the forward position.
  • Start the generator
  • While depressing the trigger on the drill, spin the drill chuck in reverse direction. This will excite the field and the generator will now produce electricity. If spinning the chuck one direction does not work, try spinning the chuck in the other direction as you may have the reverse switch positioned backwards.

Use caution not to get your hand or other materials caught in the chuck. As soon as the field is excited, the generator will produce power and the drill will turn on.

The reason this works is because the electric motor in the drill will act as a small generator when spun backwards. The magnets in the drill’s motor induce a voltage into the motor windings, which is fed back through the trigger, cord and into the generators receptacle. From there it goes into the power winding of the stator. The voltage going through the power winding creates a magnetic field, which is intensified due to the iron core of the stator laminations. The rotor intersects this magnetic field as it is spun past the power winding, thus inducing a voltage in the rotor winding. Once current flow is present in the rotor winding the rotor has been flashed.

If flashing the field does not make the generator work, you may have additional problems, besides a lack of magnetism in the rotor. Further testing will be needed. Hopefully, this will give a simple way to field flash your generator if needed.

My Generator Is Not Generating, But The Engine Runs; Help!


One of our recent customers had a small scare with their new generator. Nothing dramatic, just puzzling. The engine started normally and everything seemed 100%, except for one issue:  no electricity was being generated to the main terminals or the convenience outlet.  Frustrating to say the least.

The customer and GMG tried most of the common checks with no affect. Here were the symptoms:

  • Engine ran fine
  • No electricity at convenience outlet
  • No electricity at terminals
  • Nothing on the Hz/frequency or Voltage meter

Our customer was patient with our requests to double-check common items such as:

  • Making sure the master phase selector switch was in the 110/220 volt position (3 o’clock)
  • Making sure the master breaker was on
  • Making sure the small breaker for the convenience outlet was on (pushed in)
  • Making sure the readout selector on the Control Panel was set to the correct setting (single phase, 110/220 volt). This MUST match the Phase Selector Switch. You can play with this while the unit is running. You would want the voltage meter to read 240 volt and the frequency meter to read 60 Hz (corresponding to an engine speed of 1800 rpms).

Still nothing! Ugh! Our incredibly resourceful customer did a quick Google search and found that these symptoms are associated with a non-energized electrical field in the generator head (windings).  While the unit was running, but not generating electricity, he set the master switch to the “Start” position for 3 seconds to “flash/energize” the electrical field within the generator head. This worked!

We wanted to dig a little more deeply, so we provided the scenario to our technical staff. They had more color to add to what was going on.  As with all military generators the Master Switch is to be held in the start position long enough to start the engine AND excite the field windings in the generator itself. The operating instructions on the side of the unit states “Move Master Switch to Start position and hold until the engine runs continuously.” Even the newer units require you to hold in the start position after the engine is running to excite the field windings. Not all generators are identical. Some excite right away. Others take a few seconds. There is an Anti-Restart switch on the engine that disengages the starter after the engine starts. No harm will come to the starter after the engine has been started and the Master Switch held in Start.

Note that this is one of the many items that our tech team tests during the refurbishment process.

So, make sure to hold the Start Switch in the start position until the engine is 100% running continuously plus a couple of seconds and you can avoid this inconvenience. Manually “flashing” or “energizing” the unit is still possible by simply holding the switch in the Start position for a couple of seconds even after the unit has been running.

Hope this helps more folks out there and reduces some blood pressures! As always, send us your questions and tips so that others can benefit! Note that the above pertains to MEP-002A and MEP-003A units, but may also pertain to other models.

All Military Generators – All in One Place!


We have finally assembled what we believe is a relatively exhaustive list of past and present generators used by the US Military.  On this page, you will also see links to two versions of the:


One version was published in 2010 (MIL-HDBK-633A) and one published in 1998 (MIL-HDBK-633).  Both of these manuals have very detailed information on the specifications for each military generator.


We Have Glow Plug Kits for MEP-002A and MEP-003A Diesel Generators


We have them. They aren’t cheap, but they will help keep your unit 110% in the winter and cold starts. These will also help save your starter from over-working (same goes for your batteries). Follow link to purchase MEP-002A and MEP-003A 24v Glow Plugs.

Fuel Line Check Valve Problems


Many military generators have check valves in the fuel line system, often immediately after all of the filters, strainers, but before the injector pump. This prevents fuel from flowing backwards in the system and also helps the system hold its prime. The MEP-002A and MEP-003A units have a check valve located after the third filter in an elbow near the oil pressure gauge. It is important to ensure that this check valve is working properly. It can stick if a unit has sat for multiple months without running. Usually a blast of compressed air and some clean diesel can help un-stick the valve.  GMG recommends exercising your generator monthly for 1-2 hours at rated speed. Do not let your unit warm up or warm down. Ideally a load should be placed on the unit during exercising as well.

The NSN part number for this check valve is: 4820-01-049-1322

The manufacturer and part number is: 22962B (14834)

Only 1 check valve is used on the MEP-002A and MEP-003A units.


How Noisy Are MEP002A and MEP003A Military Diesel Generators? The Same As Honda’s Best Worksite Unit!

GMG gets this question a lot!  Many opinions can be had about the noise level of MEP-002A and MEP-003A diesel generator units.

To protect your hearing around any engine or machinery, wear hearing protection! It’s cheap and your friends and family will thank you when you’re not screaming at them or the TV is blasting!


The MEP-003A sound and noise level at 25 feet is only 77 dbA.  This is without any sound attenuation or acoustic suppression kit (ASK).

The MEP-002A sound and noise level at 25 feet is only 79 dbA.  This is without any sound attenuation or acoustic suppression kit (ASK).

For general reference, a passenger car at 65 mph at 25 ft is around 77 dbA; a freeway at 50 ft from pavement edge at 10 a.m. is around 76 dbA.  Living room music can be around 76 dbA). Garbage disposal, dishwasher, average factory, freight train (at 15 meters) can reach 80dbA.  Car wash at 20 ft (89 dbA); propeller plane flyover at 1000 ft (88 dbA); diesel truck 40 mph at 50 ft (84 dbA); diesel train at 45 mph at 100 ft (83 dbA).  Food blender (88 dbA); milling machine (85 dbA); garbage disposal (80 dbA).

Generac doesn’t even publish db ratings for any of their portable units (e.g. their GP series).  In their Q&A forum, they state: “We do not list the decibel (noise) rating of our portable generators. This is because there is no industry standard for testing decibel ratings on portable generators. Therefore, any results can be misleading or inaccurate.”  This is COMPLETE BS!  They scream louder than MEP002A and MEP003A units!

Honda’s largest “Work” generator, their EB10000 (10kw), which they claim as having the “Best fuel efficiency and lowest noise rating in its class,” has a db rating of 76 dbA. Unfortunately, they do not specify the distance from the unit (which is absolutely critical!). So, it’s safe to say that the MEP-002A and MEP-003A units are extremely similar to the largest/best Honda generator available.  My personal opinion is that a well-tuned MEP002A or MEP003A isn’t that load at all, esp. at 25 feet.  It is no louder than a high-end Honda generator.  GMG tunes every unit we sell to minimize noise and maximize performance.

For comparison’s sake here are a bunch of examples of noise levels for various items:

Note: these are examples only and may not apply to your specific work site. Noise-induced hearing loss results from a combination of high sound levels and extended periods of exposure to sounds above 85 dBA.  If the level has Lex behind it it means it was measured or is equivalent to an eight hour shift.  If the level only has dBA than it was a spot level check.


  • Augers 98-102 dBA Lex
  • Orchard Sprayer 85-101 dBA Lex
  • Tractors (no cab) 92-94 dBA Lex
  • Tractors (with cab) 77-80 dBA Lex


  • Autobody Technician 83-96 dBA Lex
  • Brake/exhaust Mechanic 82-95 dBA Lex
  • Customer Service, Manager ,and Parts Person 77-83 dBA Lex
  • Detailer 97 dBA Lex
  • Mechanic 77-102 dBA Lex
  • Painter 88-99 dBA Lex
  • Partsman   80 dBA Lex
  • Service Manager-Tire Shops 84-88 dBA Lex
  • Tire Installer 81-96 dBA Lex


  • Carpenter 86-97 dBA Lex
  • Carpenter, Framer   91 dBA Lex
  • Concrete Worker   83-105 dBA Lex
  • Drywall installer   89-91 dBA Lex
  • Electrician   89 dBA Lex
  • Elevator installer 96 dBA Lex
  • Hoist operator 100 dBA Lex
  • Ironworker   93 dBA Lex
  • Jackhammer Op  91 dBA Lex
  • Labourer  84-94 dBA Lex
  • Mobile Equipment Op.  91 dBA Lex
  • Plumber 90 dBA Lex
  • Steel Stud installer 93-98 dBA Lex
  • Tile Setter 92 dBA Lex
  • Welder  92 dBA Lex


  • Casino Dealer 78 dBA Lex
  • Fitness Instructor 90-92 dBA Lex
  • Nightclub 91-115 dBA Lex


  • Compressor 90-105 dBA Lex
  • Deck 88-100 dBA Lex
  • Engine Room 90-114 dBA Lex
  • Galley 75-80 dBA Lex
  • Sleeping quarters 50-80 dBA
  • Vessel repairs 70-100 dBA Lex
  • Wheelhouse 80-90 dBA Lex
  • Winch 90-100 dBA Lex


  • Food Services Worker 78-84 dBA Lex
  • Laundry Worker 83-89 dBA Lex
  • Maintenance 86-88 dBA Lex
  • Physical Plant Engineer 81-93 dBA Lex
  • Pot Washing/Dishwashing 80-88 dBA Lex
  • Sterilization 77-80 dBA Lex


  • Boom Boat 87 dBA Lex
  • Dozer operator 97 dBA Lex
  • Faller  102 dBA Lex
  • Landingman 108 dBA Lex
  • Loader Operator 88 dBA Lex
  • Log Sorter 90 dBALex
  • Logging Truck Driver 88-96 dBA Lex
  • Rigging Slinger/Choker 75-80 dBA Lex
  • Skidder Operator 98-100 dBA Lex
  • Yarder Operator 91-93 dBA Lex

 Mobile Equipment Operators:

  • Airtrack drill operator 106 dBA Lex
  • Cat Grader 82 dBA Lex
  • Concrete Batch Plant Operator 81 dBA Lex
  • Dozers (enclosed and open) 89-103 dBA Lex
  • Excavator 86-90 dBA Lex
  • Front End Loader 85-91dBA Lex
  • Labourer (road construction) 85-86 dBA Lex
  • Mobile Crane Operator 97-102 dBA Lex
  • Offraod Truck 82-90 dBA Lex
  • Open Packer 95 dBA Lex
  • Rock Crusher Operator 98 dBA Lex
  • Scraper Operator 96 dBA Lex
  • Skidstear Operator 96 dBA Lex


  • Backhoe Operator 88 dBA Lex
  • Electrician 89 dBA Lex
  • Engineer 96 dBA Lex
  • Grader Operator 88-90 dBA Lex
  • Labourer 85 dBA Lex
  • Lifeguard 78-90 dBA Lex
  • Mechanic 83-90 dBA Lex
  • Sewer Flushing 100 dBA Lex
  • Sewer Installation 89-100 dBA Lex
  • Sewer Worker 88-100 dBA Lex
  • Street Cleaning 89 dBA Lex
  • Truck Driver 86-98 dBA Lex
  • Welder 88-94 dBA Lex

Public Schools:

  • Automotive 83 dBA Lex
  • Band 88 dBA Lex
  • Bus Driver (gas) 83 dBA Lex
  • Food Service 83 dBA Lex
  • Grounds keeping 93 dBA Lex
  • Metalworking 84 dBA Lex
  • Music teachers 86 dBA Lex
  • PE teachers 86-89 dBA Lex
  • Tech Ed teachers 87 dBA Lex

Pulp Mills:

  • Bleach Plant 86-91 dBA Lex
  • Millwright 86-92 dBA Lex
  • Paper Machine Tender 94-98 dBA Lex
  • Screen Tender 86-92 dBA Lex


  • Membrane 82-89 dBA Lex
  • Roofer  82-98 dBA Lex
  • Roofer (shake) 95 dBALex
  • Shingle 81-93 dBA Lex
  • Tar/Gravel 84-98 dBA Lex

Retail Food:

  • Bakery Workers 78-85 dBA Lex
  • Kitchen Workers 75-87 dBA Lex
  • Meat Cutters 77-90 dBA Lex


  • Cut-off Saw Operator 82-96 dBA Lex
  • Debarker 91-94 dBA Lex
  • Dropsorter 95-101 dBA Lex
  • Edger Operator 87-102 dBA Lex
  • Green Chain 79-89 dBA Lex
  • Sawfiler 83-93 dBA Lex

Waste Management:

  • Banging on garbage bins (5 feet away) 100 dBA
  • Banging on bins:
  • Garbage Truck, cab (window open) 91 dBA
  • Garbage Truck, cab (window closed) 88 dBA
  • Behind Garbage Truck (while compacting) 89 dBA
  • Behind Garbage Truck (30 feet away) 98 dBA
  • Sewer Truck cab 94 dBA



  • Heavy traffic 70-80 dBA
  • Thunder clap 120 dBA

Home & Garden:

  • Air conditioner 60-72 dBA
  • Alarm clock ring 80 dBA
  • Average home inside 50 dBA
  • Hedge cutter 95 dBA
  • Leaf Blower up to 115 dBA
  • Chain Saw up to 125 dBA
  • Dishwasher 54-85 dBA
  • Food blender 88 dBA
  • Lawn mower 80-95 dBA
  • Vacuum cleaner 60-82 dBA


  • Aircraft, jets (cruising) 71-83 dBA
  • Ambulance siren 120 dBA
  • Apollo liftoff 188 dBA
  • Fishing (power boat) 60-115 dBA
  • Jazzercize class 90-92 dBA
  • Motorcycle 80-115 dBA
  • Movies 80-85 dBA
  • Movies 80-118 dBA
  • Private aircraft 80-110 dBA
  • Referee whistles 103-107 dBA
  • Snowmobile 86-100 dBA
  • Sporting events 95-100 dBA
  • Truck Show 90-110 dBA
  • Video Arcade 80-110 dBA


  • At the bar 90 dBA
  • Car stereos up to 154 dBA
  • Clubs and discos 91-115 dBA
  • Home stereo up to 115 dBA
  • Personal stereos 60-120 dBA
  • Rock concerts 90-125 dBA
  • Symphony concerts 80-100 dBA

Firearms Note: a single exposure to gunfire can cause permanent hearing loss.

  • .22 rifle 132-139 dBA
  • Hand guns 150-167 dBA
  • Rifles 156-167 dBA
  • Shotguns 147-149 dBA

Toy box:

  • Balloon pop 157 dBA
  • Bicycle horn 143 dBA
  • Cap gun 99-156 dBA
  • Hammer & peg board 94-97 dBA
  • Rattles 75-91 dBA
  • Toy rifle 143-153 dBA
  • Wind-up drummer 88-91 dBA


  • Circular saw 113 dBA
  • Electric drill 94 dBA
  • Power saw 95-115 dBA
  • Router 85-110 dBA
  • Snow blower 85-91 dBA

Even more comparisons:

Noise Source Decibel
Jet take-off (at 25 meters) 150 Eardrum rupture
Aircraft carrier deck 140
Military jet aircraft take-off from aircraft carrier with afterburner at 50 ft (130 dB). 130
Thunderclap, chain saw.  Oxygen torch (121 dB). 120 Painful.  32 times as loud as 70 dB.
Steel mill, auto horn at 1 meter.   Turbo-fan aircraft at takeoff power at 200 ft (118 dB).  Riveting machine (110 dB); live rock music (108 – 114 dB). 110  Average human pain threshold.  16 times as loud as 70 dB.
Jet take-off (at 305 meters), use of outboard motor, power lawn mower, motorcycle, farm tractor, jackhammer, garbage truck.   Boeing 707 or DC-8 aircraft at one nautical mile (6080 ft) before landing (106 dB); jet flyover at 1000 feet (103 dB); Bell J-2A helicopter at 100 ft (100 dB). 100 8 times as loud as 70 dB.  Serious damage possible in 8 hr exposure
Boeing 737 or DC-9 aircraft at one nautical mile (6080 ft) before landing (97 dB); power mower (96 dB); motorcycle at 25 ft (90 dB).  Newspaper press (97 dB).


4 times as loud as 70 dB.  Likely damage 8 hr exp
Garbage disposal, dishwasher, average factory, freight train (at 15 meters).  Car wash at 20 ft (89 dB); propeller plane flyover at 1000 ft (88 dB); diesel truck 40 mph at 50 ft (84 dB); diesel train at 45 mph at 100 ft (83 dB).  Food blender (88 dB); milling machine (85 dB); garbage disposal (80 dB). 80 2 times as loud as 70 dB.  Possible damage in 8 h exposure.
Passenger car at 65 mph at 25 ft (77 dB); freeway at 50 ft from pavement edge 10 a.m. (76 dB).  Living room music (76 dB); radio or TV-audio, vacuum cleaner (70 dB). 70 Arbitrary base of comparison.  Upper 70s are annoyingly loud to some people.
Conversation in restaurant, office, background music, Air conditioning unit at 100 ft 60 Half as loud as 70 dB.  Fairly quiet
Quiet suburb, conversation at home.   Large electrical transformers at 100 ft 50 One-fourth as loud as 70 dB.
Library, bird calls (44 dB); lowest limit of urban ambient sound 40 One-eighth as loud as 70 dB.
Quiet rural area 30 One-sixteenth as loud as 70 dB.  Very Quiet
Whisper, rustling leaves 20
Breathing 10 Barely audible

How To Wire a MEP002A or MEP003A Diesel Generator

This article describes common power  generation connections and discusses the use of power transformers.  This is a scanned article and there may be typos and some odd images. We tried to scan and convert this so that it is more accessible on the Internet.  Please see all the figures and pictures at the end of the text portion.

You can also download the original article written by Kenneth  Tollstam,  Jr.  Mr. Tollstam served four  years in tactical Signal battalions  in Europe.  He  has  also  served  as  the  OIC of  an electronics maintenance shop and as a C-E commodity manager for the  9th   Infantry   Division   where  he  was  promoted   to   W02. Tollstam holds a B.A. from St. Martin’s College in Washington. He recently separated from the Army.  We would like to thank Mr. Tollstam for his insight and help in educating folks on military generator wiring and electrical theory.  As always, please consult a licensed electrician before attempting any electrical work.

Download Original File Here: How-To-Wire-A-MEP002A-or-MEP003A-Military-Diesel-Generator


Some technical manuals for both communications assemblages and power generation equipment are vague in their instructions for connecting the power cables to the load terminals. The technical manuals for the power generation equipment do not give any guidance for connecting the equipment grounding conductor, EGC.  These  generators were designed  to power many different  kinds of equipment, not just communications equipment, and it is the user’s responsibility  to  configure  the  generator  to  supply   the proper  kind of power. The following will explain in detail the basic connections to be made to the common generator sets (gasoline / diesel   DOD models)   currently in use   by the military.

The gasoline driven 3 K w, S K w, and 10 K w generators are designed so that they can provide the three kinds of power described earlier at the turn of a switch. The diesel driven  IS Kw, 30 Kw, and  60 Kw generators are usually  operated to provide  3 phase,  120/208  volt, 4 wire power  into  a central distribution system.  The gasoline driven 3 Kw and  5K w generators are usually used to provide single phase, 120 volt, 2 wire power for communications assemblages. Bothe types of generators operate basically the same.  When the generators are providing single phase, 120 volt power, they provide a balanced output as illustrated in figure 9.

Between either   load   terminal   and   ground, there   is a potential of 60 volts.  Between both load terminals (across the full phase) the full 120 volt potential is present.  This can put a potential difference of 60 volts between the neutral return line and ground. This can be a source of noise to some types of communications equipment. This floating power source does not provide a neutral. If connected  improperly, there  will be no low  resistance  third  wire, EGC,  ground  to system ground (power  source  neutral), since there is actually no system ground. This can be potentially hazardous in that if a ground   fault (short circuit) develops anywhere in the system, it will not clear (trip the circuit breaker or blow the fuse). Incorrect methods of connecting to this type of power source  can  create  many  kinds  of undesirable situations to include  having  a  60  volt  potential  between  the  generator frame  or  trailer  and  the shelter.

Figure  10 shows  the  proper   way to connect the  power cable   to  the  load   terminals  of  a  gasoline   driven   3  K w generator, model  MEP-Ol6A (or  the load  terminals of the generator switch  box  on  the  trailer)  for  single  phase,  120 volt, 2 wire operation. Make sure the switch (Sl) in the generator  control  box   of   the   generator  (or   on   both generators  for a trailer  mounted set) is adjusted to the 120 volt,  single  phase  position.

The white conductor (neutral return) and green conductor (ground, EGC) should be connected to Ll as illustrated. Additionally, a  6  or  8  A WG  insulated   conductor (wire) should  be connected between  L I   and the generator or trailer ground  which in turn  should  be connected  to earth  ground. Remember, LO  is not  ground. The  black conductor (“hot” line) should  be connected to L2. Wiring a single phase,  120 volt, 2 wire primary  power this way unbalances the output  of the generator and  gives a power source  neutral.  See figure 11.

Connecting the ground line, EGC,  to the system ground (power    source    neutral)    keeps   the   potential   difference between neutral and ground  to zero, or near zero, volts. This also  provides  a low resistive ground  back to system ground (power  source  neutral) at the generator as discussed earlier.

The  principle   behind  the  single  phase,  120 volt,  2 wire power connection to  the gasoline  driven  5 K w generator is the same as that  for the 3 K w generator except  that  the load terminal   connections  are  different.  Figure   12 shows  the correct   single   phase,    120  volt,   2  wire   primary    power connection to a 5 K w generator, model MEP-0 17 A. Again, insure that  the phase selector  switch inside the control  panel is set to the  120 volt,  single  phase  position.

Sometimes the gasoline  driven  I 0 K w generator is used to provide  single  phase,  120  volt,  2 wire  power.  Again,  the power cable connection principle is the same as for the 5 Kw and  3 K w generators, except  the load  terminal  connections are  different.  Figure 13 shows  the  correct  primary  power connection  for   single   phase,  120  volts   from   a   10  Kw generator, model  MEP-003A. Insure that  the  phase  selector switch  inside  the  control panel  is set  to the  120 volt,  single phase  position.

The  10 Kw generator is often  used  to supply single  phase 1201240 volt,  3 wire  power. Other types  of generators can also provide this  type  of power. When  this  type  of power  is required,  the phase  selector switch  in the control panel  must be set to the 1201240  volt,  single  phase  position. The  output from the  load  terminals will be as  illustrated in figure  14.

When  dealing with  single  phase, 120 volt,  2 wire  power cables  with  a  third   wire  grounding conductor,  the  color coding is almost always consistent: black for “hot”, white for neutral  and  green   for  ground.  When   dealing with  multi­ phase or single  phase, 3 wire power  cables, the color  coding may differ  from  cable  to  cable. Usually  the  cable  will still have a black conductor which  will represent one of the “hot” lines. The  other  “hot” lines for the  remaining phases  may  be colored  red,  blue,  yellow  or  green. The  color green  is now used only for the ground conductor but  in some  of the older cables  this  may  not   be  the  case.  Figure  IS illustrates  the proper  way  to  connect a standard  military single  phase, 3 wire, 1201240 volt  power  cable  (issued  with  the  ANITRC- 112 Radio  Terminal Set)  to a gasoline driven, model  MEP-003A, 10 Kw generator.

Note:  The  red and  black “hot” wires may be transposed. Remember  that    Lo   is  system  ground  (power  source neutral) and  not  ground. The  ground and  neutral wire must be connected together on  Lo and  an additional wire must  be added    between  Lo   and   earth  ground.  This   insures  the connection of  Lo  to  ground. Be sure  always to  check  the pertinent  technical  manuals  before  making any   primary power  connections with  an  unfamiliar power  cable.

Connecting to 3 phase, 4 wire power  is basically the same regardless  of  the   power  source.  Almost  all   military  AC power  generators are capable of providing 3 phase, 120 I 208 volt,  4 wire power, and  the connecting procedure is the same. The  color coding from  power   cable to  power   cable   may differ, so  be sure to  check   the  technical  manual.  Figure 16 illustrates the  proper way  to  connect to  3  phase, I20I 208 volt,  4 wire  power.

The  neutral wire  will probably be white.  The  ground  wire may or may  not  be present. lf it is present, it will probably be green  or  bare.  Again, the  neutral and  ground conductor (if present) must  be connected together to Lo,  and  Lo must  be connected to earth ground to insure the ground connection. When  dealing with  10 Kw,  30  Kw,  and  60  Kw generators, make  sure   they  are  configured  to  supply I 20 I 208  volts  as these   generators are  capable of  supplying 240/416 volts. Check the  technical manual.


In  Europe  where  the  standard  commercial power  is 3 phase, 220(380  volt, 4 wire, it is sometimes necessary to use step-down  power  transformers to  operate equipment designed  to operate at 120 volts. The 3 types of transformers commonly used are the single phase autotransformer, the single  phase  isolation transformer, and  the 3 phase, 4 wire wye transformer. Most  transformer power ratings are given in kilovolt amperes (K VA) and  the load calculations are the same as  those  for  power  generators.

A good  example of a single  phase auto transformer is the TF-167.  See figure  17.

Be very careful  when connecting an auto transformer to an electrical power source. On the input side of the transformer, make certain that  the “hot” line of the input  is connected to the top of the transformer coil (terminal Z in figure 17). If the “hot” and neutral lines on  the input side of the transformer are transposed, there will still be 120 volts across the output; however,  the neutral line will carry a 220 volt potential measured  to ground all through the equipment connected to it. See figure  18.

This  can  create  a very dangerous situation. This actually caused  a  multiplex unit,  TD-754 / G,  to explode. The  TD-754/G has  an  AC  input  line filter,  as does  most  military electronic equipment. The  filter  has electrolytic capacitors between   both   sides  of  the  line  (“hot” and   neutral)   and ground. Having  a 220 volt  potential between  neutral  and ground   caused  one  of the electrolytic capacitors to  break down  and  violently  explode. This  explosion caused  major damage   to  the  equipment, bending  the entire  case  out  of shape.  The  equipment was not even  being used nor  was it turned  on; it was merely plugged  into the power receptacle.

The   correct   way         to    connect   a    single   phase autotransformer, such as the TF-167,  for supplying primary power is illustrated in figure  19.

Another commonly used transformer is the single phase isolation  transformer as illustrated in figure 20.

With  this kind of transformer, there are the same kind of floating power output problems as are encountered with the single phase 120 volt output of a power generator. Figure21 illustrates the proper  way to connect  a single phase isolation transformer for  primary  power.

The last kind of transformer normally encountered is the 3 phase, 4 wire wye transformer as illustrated in figure  22.

The output  of this kind of transformer is the same as the 3 phase, 4 wire  output of a  power  generator, and  the  load should be connected   in the same  manner.

When dealing with power transformers, there may not be any technical  r:anuals available  to refer to for information. Most transformers have  a  data   plate  which  will give the voltage  and   power   ratings   and   show   the  line  and   load terminal  configurations. Always  make  sure  that  the transformer   to  be  used  will  operate on  the  line  voltage available,  will  supply  the  voltage  needed,  and  will adequately   handle   the  load.   An  unfamiliar transformer without descriptive information, either  on the  transformer or elsewhere, should  be left alone.

The frequency of the line current, whether it is 50 or 60 Hz, will  generally  not   affect   the  operation  of  most  military electronic equipment. Most  of the power generators used m the military can supply  both  50 and  60 Hz. A transformer will supply the same  frequency  at the output that  is applied

to the input.  Because inductive  reactance  is more efficient at higher frequencies,  some  inductive  devices, such as electric motors  and  transformers, designed  to operate at 60 Hz may overheat when operated at 50 Hz. Inductive electric  motors will also  tend  to  rotate  slower at 50 Hz than  at 60 Hz. It is important to check  whether  or not the inductive equipment is  rated  to  operate at  the  line  frequency  available. If the equipment  will  only  operate at  60  Hz  and  the  only  !me frequency  available  is 50 Hz, as is the case in Europe, then a rotary power converter will be necessary.  A rotary  power converter consists  of an electric  motor  which turns  a power generator. The 50 Hz line current powers the electric  motor which  turns  the  power  generator which  produces a 60  Hz power   output.  The   same   rules   that   apply. to the  load connections and  calculations of standard military  power generators also  apply  to  rotary  converters.

Though not all the aspects  of primary  power distribution have   been  covered   in  detail,   this  article   offers   a  baste foundation from which to work. Primary power considerations are vitally important to safety,  both personal and equipment. Electric power must be treated  with respect. The  harnessing of electrical  energy  has been the single most important influence  on  our  highly  society.When electricity   goes  to  work   for  us,  every  btt  of  1t   must   be controlled. Loss of control can  result  in injury  or death.

Primary    power   considerations  are   also   important  to quality,  dependable telecommunications. No less planning should  go  into  primary  power  than  goes  into the establishment of systems  and  circuits.


TM  11-486-7 26 Apr  63 Electrical Communications Systems Engineering   Power

FM  55-506-1  22 Apr  77 Basic Electricity

TCII-6    Sep  76 Grounding Techniques






A Simple Generator Setup for Home Back-up Use


This is a great example of a MEP003A installed for home use.  The unit is place on high ground that will drain well.  Then the entire area is covered with crushed stone to aid in water transport and to minimize mud kicking up on the unit.  4 modest sono-tubes are sunk in the ground to provide ballast and stabilization to minimize vibration of the genset.  One large bolt is then set with epoxy into the concrete sonotube and then bolted to the aluminum skid that the genset is mounted on. This makes for an extremely solid, secure and tamper-proof unit.

If you want to move it, simply undo 4 bolts and place in trailer or pickup! Pretty easy.

As for fuel, this unit has the standard 12.5 gallon day tank that is fed with the on-board standard auxiliary pump that is connected to an old truck tank.  This fuel line could also directly tie into your home heating oil supply if your home or business runs on home heating oil.

A Word About Our Batteries

Below are the specs for civilian batteries for the MEP003A and MEP002A generators:

MEP003A Units:

  • Battery BCI # : BCI #24R
  • Battery Height : 9″
  • Battery Length : 10 3/4″
  • Battery Voltage : 12 Volt
  • Battery Width : 6 3/4″
  • Battery Cold Cranking Amps @ 0 Degrees F : 675
  • Battery Cranking Amps @ 32 Degrees F : 850
  • Battery Posts Type : Top Post
  • Battery Reserve Capacity (Minutes) : 115
  • Battery Weight : 40 lbs
  • Wet or Dry : Wet

 MEP002A Units:

  • Battery BCI # : BCI #51R
  • Battery Height : 8 3/4″
  • Battery Length : 9 3/8″
  • Battery Voltage : 12 Volt
  • Battery Width : 5″
  • Battery Cold Cranking Amps @ 0 Degrees F : 450
  • Battery Cranking Amps @ 32 Degrees F : 560
  • Battery Posts Type : Top Post
  • Battery Reserve Capacity (Minutes) : 70
  • Battery Weight : 28 lbs
  • Wet or Dry : Wet

New Ambac M-50 Manuals Posted


These manuals are for servicing your Ambac M-50 Fuel Injection Pumps for your MEP002A or MEP003A units. Not that we recommend that the average person attempt to service or rebuild your injection pump, but we want to provide all of the manuals we can find for you.  GMG will begin to offer a rebuild program in 2013. We will rebuild, service and test Ambac M-50 pumps and ensure that the timing button is suitable for your specific application/unit.  Stay tuned!

You can find all the manuals for the Ambac M-50 Fuel Injection Pump:  50-2/A4-80A-9540A Manuals here.

Selecting Correct Injection Pump Timing Button and Injection Pump Installation for you MEP-002A or MEP-003A Ambac Fuel Injection Pump

Selecting Correct Injection Pump Timing Button and Injection Pump Installation for you MEP-002A or MEP-003A Ambac Fuel Injection Pump

M50/PSU IF NO. 3136 1/21/2009 1 Printed in USA Rev Level A

Ambac International, 910 Spears Creek Court Elgin SC 29045(USA) – North America
Telephone: 1-800- 628-6894 Fax: 1-800-542-8230 Website:


DOWNLOAD THIS FILE:  Ambac-Timing-Button-For-M50-Injection-Pump-MEP002A-MEP003A-IF_No._3136

Selecting Correct Injection Pump Timing Button and Injection Pump Installation
Read through these instructions completely before beginning the actual installation. Perform the following steps in the order listed and refer to the illustrations for clarifications as required. Retain the packing list for use when ordering replacement parts

  • WARNING This symbol is used throughout this instruction sheet to warn of possible serious personal injury or death.
  • CAUTION This symbol refers to possible equipment damage. Remove both battery cables from the battery. Disconnect negative battery cable first.
  • WARNING Accidental starting of the engine might cause severe personal injury or death. Disconnect the battery cables when repairs are made to the engine, controls, or housing.  This instruction sheet applied to 2 and 4 cylinder Onan Diesel models DJBA, DJB, DJC, MDJB, MDJC, RDJC, MDJE, MDJF, RDJE, RDJEA, and RDJF using the AMBAC PSU or Model 50 Injection pump.
  • CAUTION Keeping the fuel system clean is extremely important. A fine particle of dirt can ruin the injection system in a very short time. If the fuel system is opened for any reason, cap all openings and place the parts removed in clean diesel fuel. Before installing new or used parts, wash them in clean fuel and install them wet.
  • CAUTION Preservative oil applied to the new injection pump during assembly may cause the pump to stick. Forcing the plunger or gear will damage the pump. Dissolve preservative by soaking pump in clean filtered diesel fuel for 15 to 30 minutes.


The timing button has a code number or letter stamped on it that corresponds with its dimension in thousandths of an inch. See Table 1. Figure 1 shows the timing button. One of these buttons will provide the correct port closing.  CODE LETTER OR NUMBER STAMPED ON SIDE FIGURE 1. TIMING BUTTON CODE M50/PSU IF NO. 3136


The injection pump on each engine must be timed to that engine by using a timing button of specific thickness. Each new pump has its port closing dimension stamped on the pump mounting flange. This port closing dimension is measured at the factory using a number 11 or standard button. Pump timing is critical. Use one of the two timing methods to determine correct new button thickness. If the correct button is not supplied with the replacement pump refer to Table 1 and order the correct one from AMBAC International.
Thickness Part No. Identification
.089” (2.26mm) BO853-10 10 or L
.092” (2.34mm) BO853-9 9 or K
.095” (2.41mm) BO853-8 8 or J
.098” (2.49mm) BO853-7 7 or H
.101” (2.56mm) BO853-6 6 or F
.104” (2.64mm) BO853-11 11
.107” (2.72mm) BO853-5 5 or E
.110” (2.79mm) BO853-4 4 or D
.112” (2.84mm) BO853-3 3 or C
.116” (2.95mm) BO853-2 2 or B
.119” (3.02mm) BO853-1 1 or A
.122” (3.10mm) BO853-12 12 or M
.125” (3.17mm) BO853-13 13 or N
.128: (3.25mm) BO853-14 14 or P
.131” (3.33mm) BO853-15 15 or R
.134” (3.40mm) BO853-16 16 or S
IMPORTANT: Plunger buttons are not included with Model 50 pumps or hydraulic heads. The required plunger button must be selected when the new pump, or an old pump with a new head is installed on an engine.


One of two methods can be used, to determine the proper timing button to correctly time the fuel injection pump to the engine.

Method 1: Timing by Calculation
This procedure is used, when all dimensions are available for replacing an old pump, before the pump is installed. Timing by calculation requires the port closing dimensions and button thickness from the pump being replaced. It also requires the port closing dimension of the new pump. Put the dimensions in the PORT CLOSING FORMULA and calculate the new button thickness. After determining the timing button thickness, find the button code in Table 1.

If injection pump is removed from the engine, make sure the steel shims between pump and cylinder block mounting remain the same. These shims maintain proper gear backlash.

CAUTION Do not change the pump mounting shim’s total thickness or the proper pump gear to camshaft gear mesh will be affected. The shim’s thickness is established at the factory during engine assembly and does not change unless a new cylinder block is installed.
PORT CLOSING FORMULA: The formula for determining the proper port closing (PC) timing button for a new or replacement pump is as follows:
1. Remove old pump.
2. Determine port closing dimensions and original button thickness from old pump.
A. Write down port closing dimension given on old pump flange and port closing dimension given on new pump flange. See example.
B. Use a pair of channel lock pliers or screwdriver to remove tappet, retaining ring, and timing button from old injection pump (Figure 2). Use number or letter code on timing button to obtain dimension of old timing button from Table 1. This code should be the same as the code number stamped on injection pump (figure2).
CAUTION On all PSU pumps be sure to hold the pump drive gear securely to the pump body when removing the tappet. If not, the pump will come apart and be difficult to assemble. The metering sleeve will drop off the plunger if the gear and plunger are removed. If the plunger port is not enclosed by the sleeve, there will be no fuel delivery and the pump will not operate.
3. Add dimension on old pump flange to timing button dimension. See example:
Example: Inches (mm)
Port closing dimension of old pump 1.109 (28.168)
Button thickness of old pump +.107 ( 2.719)
Total 1.216 (30.887)
Port closing dimension of new pump -1.094 (27.788)
Required button thickness of new pump .122 ( 3.099)
4. Subtract port closing dimension given on new pump flange from total dimension for old pump.
5. Use dimension calculated to select new timing button that is nearest the calculated dimension. Install new timing button in pump and install tappet on pump.
6. Install injection pump. Refer to INJECTION PUMP INSTALLATION.
Be sure the steel shims between the pump and the cylinder block mounting are the same. These shims maintain proper gear backlash. The number stamped on the cylinder block injection pump mounting pad indicates the proper shim thickness. This thickness does not change when a new pump is installed. It only changes when a new cylinder block is installed.
1. Turn engine in direction of rotation (clockwise when viewed from the front of engine) until number one cylinder is on a compression stroke and the PC mark on flywheel lines up with timing pointer on gear case (Figure 0206). Rotation clockwise also takes out all gear backlash in that direction.
Look into injection pump mounting hole to verify that one intake lobe points outward and down 45 degrees.
2. Remove screw (Figure 9) on side of injection pump. Rotate drive gear until a .125 inch (3.175 mm) brass rod can be inserted into drive gear slot. This locks the gear in position when installing injection pump on engine.
3. With injection pump drive gear locked, place pump in mounting hole. Hold pump firmly against cylinder block. A slight spring pressure indicates that the pump and camshaft gears are meshed (Figure 10).
5. If gears mesh, secure pump using a flat washer, lock washer, and nut on each stud. Torque nuts evenly to 5 to 16 ft.-lb. (20 to 22Nm).
6. Remove brass rod and install timing hole washer and screw.
Method 2: Flow Timing Injection Pump
Use this procedure to time pump when dimensions from old pump are not available. Begin by installing pump which has been fitted with standard timing button (may be unmarked or marked number 11).
1. Refer to Fig. 0210 and remove cap nut from delivery valve and delivery valve holder,
then lift out delivery valve spring. Reinstall holder and cap nut. Note that early models do not have a delivery valve holder.
2. Rotate flywheel until PC mark on flywheel is about 15° from timing pointer in
compression stroke of number 1 cylinder. Place fuel control at full speed position. Disconnect high pressure line from number 1 injector. Operate transfer pump priming lever (fuel should flow from disconnected injector line) while slowly turning flywheel clockwise. When fuel flow from line stops, this is port closing point and beginning of injection. At this point, port closing (PC) mark on flywheel should be aligned with timing pointer if timing button is correct.
A. If timing pointer is ahead of port closing mark, timing is early and a thinner button is needed. If timing pointer is between PC and TDC marks, timing is late and a thicker button is must be installed.
B. To select correct button size, carefully measure space between PC mark and timing pointer. Each 0.100 inch (2.54mm) on flywheel circumference is equivalent to 0.003 inch (0.076mm) button thickness. Refer to table 1.
Example. Standard button installed in pump for test is 0.104 inch (2.642 mm) thick. Flow of fuel stops 0.2 inch (5.08mm) after PC mark is passed indicating late timing. Referring to table 1, it will be noted that button of code 4 or D is 0.110 inch (2.794mm) thick or 0.006 inch (0.152 mm) thicker than standard button. Installing this button in place of test button should time injection pump correctly.
3. After pump is correctly timed, reinstall delivery valve spring. Tighten delivery valve holder to torque of 65-70 ft.-lbs.. (90-95 N·m) and cap nut to 55-60ft.-lbs (75-80 N·m). Complete installation of pump as outlined.

Electric Motors and Power Systems

There seems to be a lot of confusion about the voltage standards for motors and why they are structured the way they are. There are, of course, two broad categories of motors, AC and DC. The voltage standards for these two decidedly different motors are much different from each other. It will be the goal of this paper to try to reduce some of the confusion that exists in the AC motor voltage standards.


To understand how voltage standards for motors are set it is important to know the basics of the power systems they operate on. In general, utilities that supply power in the USA, and most other 60 cycle countries, are required to provide power to the incoming point of a facility in multiples of 120 volts. Thus incoming equipment, such as circuit breaker panels, are rated in multiples of 120 volts. The common voltages are 120, 240, 480, and 600.

In addition, utilities are obligated by the regional governing authorities, (usually called Public Utility Commissions) to regulate the voltage within a fairly narrow range such as plus or minus 5%.

For example, in most single phase residential systems the voltage is 120/240. It is brought to the building with 3 wires, one being a neutral and the other two having voltages 120 volts different from the neutral wire. The voltage difference between the two “hot” wires is 240 volts.

In 3 phase systems the situation is a bit different. There are 3 phase, 3 wire, ungrounded systems where the voltage between the three wires is 240 volts. The big brother of that system is the ungrounded 3 phase, 3 wire 480 volt system. Ungrounded systems are usually found in older facilities.

In newer installations, the two most popular systems are called 4 wire grounded wye systems. The low voltage version is represented by a 120/208 volt system. The higher voltage version it is a 277/480 volt system. On both of these “grounded wye” systems, the low voltage portion (120 or 277 volts) is only available as single phase. The high voltage (208 or 480 volts) is available as either single phase or 3 phase. It should be noted that in the 4 wire grounded wye systems the high voltage is 1.73 times (the square root of 3) higher than the low voltage. These grounded wye systems are generally felt to be safer and more flexible than the older ungrounded systems. The flexibility comes from the ability to handle single phase lighting circuits, that operate at 120 volts or 277 volts, from the same system that feeds the 3 phase circuits for motors, equipment for heating, air conditioning, elevators, and industrial machinery.


Now to discuss motors that operate on these 60 cycle power systems. In the case of “utilization equipment”, such as motors, the voltage standards have been selected in multiples of 115 volts. For example, 115, 230, 460 and 575 volts. The standards for the “utilization equipment” have been deliberately picked to be slightly less than the utility delivery voltages because in an industrial plant or large commercial building there may be several hundred feet between the incoming service point and the equipment. The distances involved will always lead to some voltage loss (or drop) through the wiring. On short runs this might be very small, even less than a volt, but on long heavily loaded runs it might be as much as 3 or 4% of the operating voltage. So choosing the utilization voltage to be different — and less than — the utility service voltage makes good sense.

There is also another factor that should be mentioned. The design standards for utilization equipment are set so the equipment is able to handle a voltage variation of plus or minus 10% of the nameplate rating. Thus a motor nameplated at 460 volts should be able to be operated successfully up to 460 plus 10% (506 volts) and down to 460 minus 10% (414 volts). If everything is right with the voltage of the system being in multiples of 120 plus or minus 5% and the equipment voltage being multiples of 115, plus or minus 10% then everything fits together like a neat jigsaw puzzle.

There is one oddity in the mix. That is 3 phase motors for the 120/208 volt power systems. For example, if the power system were to be 208 volts minus 5% (approximately 198 volts) and you were using a 230 volt motor, then the 230 volt motor could only go down to 207 volts (-10%) without being in trouble. There would be a discrepancy between the 198 volt low range of the system voltage, and the 207 lowest operating voltage of a 230 volt motor, this could spell trouble. So how can this be addressed?

There are two ways that motor manufacturers have faced up to the problem. The first is to provide motors rated for 200 volts that can operate successfully down to 180 volts, or up to 220 volts. This is an adequate margin to cover the normal range of voltages that could be expected on a 120/208 volt system. But using this approach exclusively would mean that the complete inventory of motors in all sizes, enclosures, mechanical configurations, etc. would have to be duplicated to handle the motor requirements for the 120/208 volt power systems. This would be very expensive and cumbersome, especially with the wide variety of small motors (under 10 HP) that exist.

So most motor manufacturers have taken a different approach to handling these smaller motors. This approach is that by using a somewhat more conservative design on the 230 volt motors it is possible to create a 3 phase, tri-voltage motor with voltage ratings of 208-230/460. With this approach the 230 volt winding ( and connection diagram) is used on the 208 volt power system. When this approach is taken the motor manufacturer is essentially saying that this motor can be successfully operated on voltages as low as 208 minus 10% or 187 volts. This approach usually works very well since 208 volt power systems are normally used in small buildings with relatively short distances between the incoming power service and the utilization equipment. These short runs tend to make 208 volt power systems quite stable so that the limit of the motor’s low voltage capability is seldom tested.

On motors larger than 10 HP the 200 volt motor is generally the best choice, but in many situations 230 volt motors are frequently and successfully applied on the 208 volt systems. In some cases a derate table is provided for the “low voltage” situation. In other cases the motor service factor may be reduced from 1.15 down to 1.0 when it is applied to a 208 volt power system.

Table 1 summarizes this information to show the power system voltage and description along with the motor voltage rating for single and 3-phase 60 Hertz motors.


There seems to be an endless array of possible combinations, but most of them do make sense. In 50 hertz areas virtually all power systems are of the 4 wire, grounded wye type. A typical arrangement would be a 220/380 volt power system. In this case, as in the case of a 120/208 volt 60 hertz system, the (low voltage) 220 volt power is only available as single phase and the 380 volt power is available as either single or three phase.

As a result of the voltage being described as 220/380 we frequently see specifications indicating that 3-phase motors be wound for 220/380. Although feasible to do this, it is unnecessary because the 3-phase motors will only be operated on 380 volt 3-phase power. Some of the most popular voltages are 220/380 and 240/415. Recently European countries have recognized the problem of trying to provide equipment for these two different voltage standards and have come up with a standard that splits the difference. The new standard is 230/400. What this means is that if the motor has an adequate amount of tolerance it can run on either a 380 volt system or a 415 volt system without being damaged. Also in most 50 Hertz systems, unlike the domestic systems, the equipment voltage rating tends to be the same as the supply voltage. In other words, 380 volt motors are used on 380 volt systems as opposed to situation in this country where the equipment utilization voltage is deliberately set lower than the supply voltage.

Table 2 shows some typical supply voltages and the appropriate equipment standards for 50 cycle power systems.

When dealing with foreign voltage requirements it is always desirable to check the specified voltage against the listing of available voltages indicated in a U. S. Department of commerce booklet, Electric Current Abroad*. If the specified voltage and frequency does not match the voltages shown in the booklet for the country and city involved it should be a “Red Flag” that would suggest that the customer be contacted and the voltage confirmed for accuracy. Mistakes can be very costly!!

*Copies of Electric Current Abroad are available from your local Baldor District Office.

(1) On some systems grounding of one leg may be utilized.
(2) Some Single Phase equipment may be rated for 265 Volts.
120/208 3 Phase 4 Wire
Grounded Wye (A)
208 – 230
208 – 230
240 3 Phase 3 Wire
Delta Connected (B)
(Normally Ungrounded)
208 – 230
208 – 230
3 Phase 4 Wire
Tapped Delta (C)
Neutral Grounded
208 – 230
208 – 230
277/480 3 Phase 4 Wire
Grounded Wye (A)
265 (2)
480 3 Phase 3 Wire
Delta Connected (B)
(Normally Ungrounded)
460 460
600 3 Phase 3 Wire
Delta Connected (B)
(Normally Ungrounded)
575 575
2400 3 Phase 3 Wire
Delta Connected (B)
2300 2300
4160 3 Phase 4 Wire
Grounded Wye (A)
(1) Alternate Rating
115/200 3 Phase 4 Wire
Grounded Wye (A)
127/220 3 Phase 4 Wire
Grounded Wye (A)
220/380 3 Phase 4 Wire
Grounded Wye (A)
230/400 3 Phase 4 Wire
Grounded Wye (A)
240/415 3 Phase 4 Wire
Grounded Wye (A)
250/440 3 Phase 4 Wire
Grounded Wye (A)
220 3 Phase 3 Wire
Delta Connected (B)
220 220
440 3 Phase 3 Wire
Delta Connected (B)
440 440


Matching motors to the power system voltages can be fairly simple if the basis of the systems is understood.

Typical 3 Phase Transformer Connections



Fuel Consumption For Diesel Generators

This chart estimates diesel fuel consumption for a generator based on the size of the generator and the load at which the generator is operating.  Please note that this table is simply an estimate. Many other factors will affect the fuel efficiency of a diesel generator including design, fuel quality, air quality, and frequency of load changes.
Note that the table below does not account for smaller more residential units like the ones we sell.  Our 5kW units that are  very underrated by the U.S. Military would consume (assuming 65-100% load) roughly 0.42 gallons of diesel fuel per hour.  Lower load would consume less and more load (i.e. pushing 100% continuously for an hour) would consumer more.  The range at the low end would be around 0.25 gallons per hour and 0.60 gallons per hour at the high end.