Why Buy a Military Generator and FAQ

How much is shipping within the US?

These things are heavy and indestructible, so they cost a bit to move around!  We always attempt to get the best shipping costs we can.  We load at our facility and offer lift-gate service at your residential location (Choose Location Type = Residence).  If you have a business/commercial location with access to a crane, forklift, tractor or loading dock, we can save you a little money (Choose Location Type = Business with Dock or Forklift).  Shipment is primarily dependent upon weight, so larger units cost a bit more than smaller units. Note that this estimate includes lift-gate residential service on your end. Payment in full for both shipping and the unit is due prior to the unit leaving our facility. To learn more about shipping, go here.

Why would I want a pre-owned generator, when I can buy a new one? Excellent question!  GMG believes that buying something that was used before can be an excellent choice for multiple reasons:

  • First, you can’t buy this type of generator at your local big-box retailer:  Buying the equivalent generator new would be cost prohibitive for the typical consumer; costing easily over $10,000. Our generator sets, or gensets for short, were made for demanding military use, not for the occasional power outage or picnic.  US soldiers’ lives depend on these gensets to power radar, machinery, medical equipment and a host of other devices requiring dependable clean power.
  • Second, GMG firmly believes that buying products that are worth fixing is good economically and environmentally:  We aren’t your typical tree-hugger, although we love and protect the outdoors as much as anyone, but buying products that aren’t disposable is good for the environment.  Our gensets are good enough to be overhauled when needed — and that isn’t for 10’s of 1,000’s of hours of use, when properly cared for (mainly filters and oil changes!).  Big-box retailers’ generators, even those with quality Honda gas engines or even low-end diesel gensets, simply will not last and are, 99% of the time, not worth fixing.  They are disposable and headed for landfills after they fail.  Most gensets purchased at local retailers will most likely fail during your ownership, often at the worst time! Ask anyone who has owned a big-box generator:  Is this your first generator? More than likely, that person has owned multiple generators.  If you have a cabin or home off-the-grid, what number generator are you on?  As my father always said, “You buy cheap, you buy twice!”

What exactly is better about GMG and military surplus generators?

There are many reasons that GMG military surplus generators are far superior machines than anything you can reasonably buy new or at a big-box retailer:

  • Low RPM engines:  Our engines run at 1,800 RPMs (revolutions per minute) versus 3,600 RPMs for almost anything you may encounter online or at your local retailers. Ask them if they have a low 1,800 RPM generator — if they understand your question (and that’s a big IF), they will most likely say no. Low 1,800 RPM engines last virtually forever because they run more slowly and at lower temperatures – thus causing significantly less wear and tear on critical engine components.  The vast majority of consumer generators use standard gas engines (e.g. Briggs & Stratton, Honda, or Kohler).  While these are good companies with solid products, using a standard gas engine to power a generator that might need to run for 48 hours (or weeks in the case of our military generators), is simply inappropriate.  These are the same engines used in devices such as lawnmowers.  The main differences between these two use-cases is twofold. First, the lawnmower can be restricted or governed to a lower maximum RPM, thus extending it’s life. But to generate electricity, these types of engines must turn at 3,600 RPM (more on why later).  As soon as you fire up a consumer generator, it is running in a panicked state at 3,600 RPMs. It is simply a matter of time before the engine will irreversibly overheat and cause a catastrophic failure.
  • Diesel dependibility:  OK, we admit it, we love diesel! We don’t love it for the initial price one typically has to pay for a piece of diesel equipment, but we love low maintenance and long life! We wish our human bodies could run on diesel!  Why is diesel better?  First off, diesel fuel shelf-life is much longer than gasoline. Even though this is true, we highly recommend diesel fuel stabilizers, that also clean engine and, in winter, help keep your diesel fuel from gelling.  It is sad, that when many user go to fire their gasoline generators, they find that they can’t because the fuel has turned to varnish and clogged critical parts of the engine including fuel tank, fuel lines and carburetor (a part that a diesel engine doesn’t need!). Why would anyone put gasoline in a generator that they don’t use that often?!  Secondly, the efficiency of diesel is superior to gasoline
  • Beefiness:  It’s hard to come up with a word that describes the ‘over-builtness’ of our generators, but weighing in at 960 lbs for a 5 kW genset is not a random fact. A 5,000 kW genset at Lowes (e.g. Generac 10,000 Watt Generator) weighs only 250 lbs.  Putting the Wattage rating aside, you are left scratching your head as to why our generators are so much heavier. Every element of our generators is built to last. There is more aluminum in the engine block, more copper in the generator, a beefy aluminum skid mount (to minimize vibrations) and the list goes on and on.  Diesel engines always weigh more than their gasoline cousins because their engines must withstand much higher compression ratios, (20:1 for a typical diesel engine vs 8:1 for a gasoline engine).
  • Single or Three Phase Compatible:  Most homeowners won’t care about this feature, but a mechanic or farmer with special equipment will value the option for Three Phase electricity.  Please see Wikipedia for more on Three Phase Power.
  • Aluminum Skid Mount:  Most people don’t even think about this when purchasing, but engines vibrate (a lot!) and this generally needs to be minimized to minimize wear and tear on the engine. All of our engines come mounted on aluminum skid mounts — a $200 value in itself. No rickety tubular system with bolts that will shake loose!

Why buy a Diesel Generator?

Diesel generators are more reliable. Diesel fuel is basically a light-grade oil. Inside any internal combustion engine, there are many moving parts that create friction. Gasoline and propane are solvent-based fuels which promote friction and wear. Diesel, being a lubricant, reduces friction and wear. If you ever need to do work on a Diesel engine, they are simple. All you need to make a Diesel run is air-compression and fuel. Diesels don’t need sophisticated (and failure-prone) ignition systems; no spark plugs, no points and no carburetor!

What are the standard filters I need for maintaining my MEP002A or MEP003A?

Oil Filter: Fram CH6PL (Recommended, comes with proper gasket); Wix 51004 (BUT make sure you get gasket 5108); Napa 1004 (BUT make sure you get gasket 5108); NSN 2940-00-580-6304 Fuel Filter cartridge: Fram C1125PL (Recommended, comes with proper gasket); Wix 33113 (Tangs inside the filter have to be bent); Napa 3113 (Tangs inside the filter have to be bent); NSN 2910-00-287-1930 Fuel Strainer cartridge: Fram 35070; NSN 2910-00-222-2216 Air Filter cartridge:  Wix 42222; Napa 2222; Donaldson P10-1222; FleetGuard AF437KM

How long will a Diesel Generator last?

With proper maintenance, a high-quality Diesel generator will last indefinitely. It is important to change the oil regularly and keep the air filter clean. Clean fuel is extremely important.

What about the generator end. How long will it last?

Although it is often referred to as a generator, we only use brushless alternators. The beauty of a brushless alternator is that it only has one wear item – a sealed ball-bearing that is rated for 100,000 hours.

What about 3600 RPM Diesel Generators. Why are they cheaper?

3600 RPM Diesel generators are sometimes referred to as portable Diesel generators. They get their power from speed rather than displacement. For that reason, they weigh less than half of an 1800 RPM Diesel Engine. The alternator on a 3600 RPM Diesel generator spins twice as fast so it can get by with less than half of the copper of an 1800 RPM alternator.  Due to the higher engine speed, these 3600 RPM generators tend not to be as durable as 1800 RPM generators.  We offer very high quality 3600 RPM generators, which are much lighter and more portable than our 1800 RPM generators.

Can I run my Diesel generator on Bio Diesel or other alternative fuels?

Yes, a Diesel generator will run on almost any type of oil. They will run on anything from used motor oil, vegetable oil, refined bio Diesel, you name it. Now, should you run your Diesel Generator on any oil-based substance it will run on? If it’s an emergency, yes. However, make sure it is clean. If it is not an emergency, select your Diesel fuel alternatives carefully.

Why do some companies advertise slow Diesel Generators with 3600 RPM alternators on them?

3600 RPM alternators are very cheap to buy. With belt-drive, you can slow an engine down below 1800 RPM and speed up a generator to 3600 RPM and still get 60Hz. We don’t resort to short-cuts like this. Belt-drive, in itself, is okay if properly tensioned, however we would never couple a slow Diesel to a 3600 RPM alternator because they are capacitor-regulated and often fail. Two-pole or 3600 RPM alternators are sometimes referred to as “throw-aways” because when they fail, they are simply not worth rebuilding. Capacitor-regulated alternators also have a very low motor-starting ability. We recommend you avoid these types of Diesel generator sets and the companies who sell them.

Diesel Generator kW (General Info)

Diesel generator kW (k=1000 W= Watt) is typically produced at lower RPMs. Example 8kW =8000 Watts. It takes 1.5 horsepower to make one kW. Turning at a slow 1800 RPM a Diesel generator kW requires large displacement. Most gas and even some Diesel generators run at 3600 RPM. This is considered high speed throw away generators. Initial cost on these is low however they ware out quick and are not worth fixing. We only sell Diesel generators that run at 1800 RPM. Diesel generator kW produced from 1800 RPM engines and generators last almost indefinitely. That is why they are sometimes referred to as investment grade.

How much diesel fuel do units consume per hour at various loads?

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.  10kW units consume roughly double the 5kW unit.  All of our generators run most efficiently (power output per unit of fuel) at around 70-80% of rated load. Our 2 kW and 3kW units are single cylinder and are very very efficient on fuel consumption.

41 thoughts on “Why Buy a Military Generator and FAQ

  1. GMG says:

    That is a large unit for prime power. Military does not make one with 120/240 in that size. Only the 10kw (MEP803A) could support that, but might not meet your requirements for size.

  2. kevinw says:

    We need to buy a Generator for a customer. he needs a 30KW and his power needs are 120V /240 V
    He wants one in great shape. Could you have someone get in touch with us with a recommendation please. Kevin at PowerPlus 714-635-9264 KevinW@PowerPlusOnline.com

  3. gmg says:

    Yes. We have generator heads off of MEP002A, MEP802A, MEP003A, and MEP803A units. We would need to test them, which takes time. Where are you located? Please drop us a note with your response via our contact page. Thanks, GMG

  4. gmg says:

    Yes, they product clean power. They are not an inverter so pure sine wave versus not, is not the issue here. If you want to protect devices from power abnormalities, use a UPS between generator and device(s). Make sure it is rated to handle the load of the device(s) you are powering.

  5. gmg says:

    First off, this is probably not a sine wave purity issue, but a voltage issue. Military generators are excellent quality and much less susceptible to fluctuations in voltage. Smaller and poorer designed generators are more susceptible to fluctuations in voltage. There is a good chance that your device shut down due to an over/under voltage situation than a sine-wave situation (pure since wave vs not pure). Dirty power can be produced with poor voltage regulators, governors and simply overloading generators that cause Hz fluctuations (i.e. engine speed falls) and/or voltage drops (overloading, too long a run). The whole Pure Sine Wave vs not is about inverter technology, not generators. Generators have dirty power due to misuse, being undersized/overloaded, or having poor voltage regulators or other components that cause fluctuations in Hz and Voltage output.

  6. gmg says:

    First off, this is probably not a sine wave purity issue, but a voltage issue. Military generators are excellent quality and much less susceptible to fluctuations in voltage. Smaller and poorer designed generators are more susceptible to fluctuations in voltage. There is a good chance that your device shut down due to an over/under voltage situation than a sine-wave situation (pure since wave vs not pure). Dirty power can be produced with poor voltage regulators, governors and simply overloading generators that cause Hz fluctuations (i.e. engine speed falls) and/or voltage drops (overloading, too long a run). The whole Pure Sine Wave vs not is about inverter technology, not generators. Generators have dirty power due to misuse, being undersized/overloaded, or having poor voltage regulators or other components that cause fluctuations in Hz and Voltage output.

  7. hp429 says:

    Do the MEP-803 generators produce a nice clean pure sine wave alternating current? My concern is that my heat pump compressor and blower motors will not run properly on generator power. I have had problems with them powered off my portable 3600-rpm generator. This is for 120/240v-single phase to a residential home.

  8. Adam G. says:

    I have been running a Chinese knockoff of the 5kW Yanmar design to power my house during outages for the past 12 years. It is a great design, but I still have issues with some electric appliances due to the “dirty” AC power it produces. I don’t have an oscilloscope to prove it, but that is my best guess. I would like to get an 1800 rpm 5, 10, or 15kW genset, but I am concerned that my appliances still may not operate on generator power. Can you attest to how pure of a sine wave the MEP series produces, so that I can run my microwave, heat pump, blower fans, etc?

  9. gmg says:

    Free MEP803A Manuals can be found by following this link.
    Free MEP805B Manuals can be found by following this link.

    You can find control panel / dash LED bulbs for these units here.

    We do not sell transfer switches, only the remote start kits that work with transfer switches. You can find MEP802A and MEP803A remote and auto start kits here. If you purchase, please note during checkout which exact model you are purchasing the remote start kit for.

    An approved electrician should be consulted to ensure the pieces work together (i.e. your transfer switch with our remote auto start kit). They can also help size the cable needed for your length of run and situation (direct burial or burial in conduit).

  10. meplein says:

    bought two units ,one is 2012 Fermont MEP 803A ,serial # F247545,
    10kw ,need operator manual and parts manual for this one, and the other is 2008 L3OFNW8 MEP-805B 30kw
    serial # 030220070405/HX36239
    and i’m in need of both manuals for this unit and also bulbs for dash lights and jack for trailer if available, plus transfer switch for these units. Ihave underground service .

  11. gmg says:

    Impossible to be sure what your needed load would be. A MEP003A or MEP803A is a best guest. But you really need to add up all the loads that would be required when the power goes out (realistically). Add up the pumps, electric appliances and electric water heaters that need to be run. Do not include the items you can live without (e.g. ACs, electric dryers). This is a detailed math addition problem where you need to add up all the items that would/could/need to be run at the same time (your worst realistic load).

  12. gmg says:

    The on-board setup on most military units is a secondary tank always fills the day tank which feeds engine. I would not change this. Why not use the same fuel mixture in both tanks and simply put a tank heater on the day tank?

  13. gmg says:

    Either 15kw or 30kw would be the closest. These are CONTINUOUS DUTY ratings. The MEP004A or newer MEP804A (15kw) or MEP005A or newer MEP805A (30kw).

  14. Shannon neth says:

    We need a military generator that can power two houses and a water pump and all in one generator .. something that can power a small farm with two houses water pumps..

  15. Dave says:

    As a residential contractor, we often use 25kw towable rental generators for framing and building homes. What would be the military diesel equivalent?

  16. James says:

    Using the auxiliary tank feature found on many surplus generators, is it possible to have a generator that can switch between the standard diesel tank, and a heated tank of WMO/WVO? The diesel would be for starting and stopping while the filtered waste oils would be the main cheap fuel.

  17. gmg says:

    We would need basic power requirements. All can generally output 240v. What overall capacity in Kw? Please use our contact form to reply so we can help you. We have a great MEP002A and the newer generation MEP802A in stock and ready to ship.

  18. Melvin A. York (BSEE/MBA/PMP says:

    I am consulting with a client as a systems engineer to configure a mobile water filtration system compatible with lose of infrastructure due to floods/hurricanes. Due to environment of unit field operation, I am recommending a rugged military grade AC field generator for electrocoagulation of the configuration. Please provide price ranges for your generator with 240 V plus out put.. Prefer USA source. (M.A. York BSEE/MBA/CMC/PMP)

  19. gmg says:

    Not worth it. You need a new generator head and distribution box. If you get the 60Hz unit, you will have a good parts unit for engine issues and some other pieces.

  20. gmg says:

    MEP003A or MEP803A generator head would be good. Depends on what your desired output would be (single or three phase and voltage). But these heads can be set up for single or three and various voltages that should be good.

  21. gmg says:

    No, not at same time. The 36,000 load itself will required 10kW. Assuming all of your loads are three phase, 208, 100 amps would require far more than 10kW itself (28kW). But this all depends on what the requirements of this 100 amp panel is. If all 208v three phase, no.

  22. Bruce says:

    I have a 803a gen.
    I want to run a 36,000 btuh 208 3 phase military ac/ heater for a trailer and provide power for 100 amp panel to live in trailer
    Can i do both whith this gen? Thanks

  23. Scotty says:

    Hi! I’m building a PTO/genset setup for my 12v dodge service truck. I have about 40hp available and mechanically governed. I’m looking for a 8kw to 12 kw weatherproof generator head. Got some thoughts?

  24. Johnny Clements says:

    I’m in search of a 60kw 3 ph generator head. It will mount to a 6cyl Detroit diesel. It is used to run an old sawmill with 75 hp motor. My gen head went out, 1958 model Hol-Gar. Searching for a replacement

  25. gmg says:

    Yes, but only one small AC. THe MEP016D is either all 120 or all 240 out of the box. If you keep all loads to 120v, you will not have to balance two hot legs. Balancing hot legs gets more and more difficult (or less and less efficient) the smaller the generator. But a refrigerator, oil burner control system, TV, lights, and an AC should be no problem. A little more detail on the oil burner would be good though. Is this simply the control system or are there large central forced-hot-air fans. If the latter, you need to see what they require in terms of load. 3kw can be increased to at least 25% more as the military underrates their units.

  26. Ed says:

    Looking to run a refrigerator, oil burner (furnace), TV, a few lights and maybe a window AC or two during the summer. Will the MEP-016D 3KW Yanmar version handle this load? What is the distortion on these units – safe for TV & computers? Are they super loud?

    My electrician has already installed a line underground to our detached garage with a 30amp style plug. The idea would be to plug in the generator outside the detached garage and then go to main panel in the house and flip the interlock breakers. Will that setup work with the 3KW version?

  27. gmg says:

    All US Military gensets are exempt (if needed) from many regulations. I am not saying they are not compliant. It varies by generator. For example, the Yanmar engines on the MEP531A is exempt from certain regulations. The UL2200 regulation is a genset regulation, not specifically dealing only with environmental issues. Our units are also not new, which exempts them from many regulations that only apply towards NEW gensets being sold and marketed in the US.

    Here is a link to the gruesome UL codes: http://ulstandards.ul.com/standard/?id=2200 Look at the table of contents, there are dozens and dozens of requirements to be certified. This is NOT LAW. This is the UL only. Do not confuse environmental law with UL requirements that are industry specific and created.

  28. Ted Lane says:

    Hello, I am in the market for a used diesel generator. I’ve been looking around at a lot of options but think the 803a is my best option. A couple local people have said that Wasington state requires diesel generators to be UL2200 compliant. From me research, that seems to raise the cost considerably and only a few manufacturers are compliant. Are military generators exempt from local environmental laws? Thanks for your views!

  29. Ken says:

    I am looking to supply an electrical load of up to 230 volts at 25 amps. Since this will be in Africa, it is 50 hz. Would your MEP-802a meet these requirements? If the problem is the 50 hz, is there an external transformer/inverter unit you recommend to step down the frequency to 50 hz? BTW, where in your product descriptions can a person find the types of outlets and amps on the units? thanks.

  30. Bobby Harris says:

    I was wounding if you sell generator heads to fit a Westerbeke 5.5 kW or knows someone who might have a recondition head . Thanks for your time

  31. gmg says:

    All things being equal, 1800 rpm is better than 3600 rpm. Most 1800 rpm units are larger, heavier and have beefier components including larger generator heads vs 3600 rpm units. Our 3600 rpm units are all diesel vs most big box which are gas. Our smaller 3600 units are Yanmar-based, which we believe is one of the best small diesel engine makers in the world. Comparing diesel to gas is a very long discussion and we prefer diesel for the longevity of the engines, ability to store fuel longer and for it’s overall fuel efficiency. In summary, our units are all diesel and rated for continuous use whether they are 1800 or 3600 rpm units. Most big box are NOT rated for continuous use (their genheads will literally overheat and break-down if run for too long).

  32. Mike Sears says:

    If the big box 3600 rpm generators are shorter lived, run hotter, etc., what about your 3,600 rpm generators that are rated for continuous use? How much better are they than the gas ones? Compare your 3,600 rpm ones with your 1,800 rpm ones.

  33. Robert says:

    I checked with my small parts house here for filter availability. He only carriers WIX and I see that you mention having to bend tangs on the fuel filter. Since I cannot purchase FRAM here, what do you mean with the tang bending and what would happen if you did not bend them if they are a direct cross for the FRAM filter? Thanks, Robert

  34. gmg says:

    Please feel free to comment on our FAQ or contact us with questions you may have about one of our Military Diesel Generators. Call us about parts as well. Our manuals are always free and are incredibly detailed.

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