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.

52 thoughts on “My Generator Is Not Generating, But The Engine Runs; Help!

  1. GMG says:

    Please consult manual. Could be many things such as bad generator head (short, bad winding, diode problem). Need to check the windings. Seems like engine is good, yes? Could also be other issues (e.g. voltage regulator or a relay issue).

  2. ronaldxhxh says:

    have a 10k old military gen. runds great BUY no currant.Has a toggle swith to flash.holding toggle switch down will generate enough power to make a 60 watt bulb light but dim .release the flash switch and bulb dies and all meters go back to 0 any clue?

  3. GMG says:

    Not 100% sure your description of issue. But you must check breaks in the coach as well as on the generator. If you have reset all breakers and tested both hot legs (assuming you have a 240v setup), and one leg is bad, you need to check continuity for that circuit. Could be a bad winding or connection on that leg. Need to check before and after the master breaker. It could be a bad breaker as well or a stuck breaker. Sometimes a leg can get stuck open (hence why you need to check power just before and after breaker to pinpoint failure point). If you have good power in both legs before breaker, you know it’s a malfunction of the breaker. Check to make sure your grounds and neutral circuits are also good.

  4. Mugi says:

    22 kw open type generator in engine running ok , electric current not coming but unload time current coming , loading time current no coming. So what problam

  5. Shawn Lafollette says:

    I have an Onen 4.0 RV in my motor home. Had 250 hours on it when I got it and now I have 600 hours now. I was using the outside outlet on an electric water heater I use in the shop for some hot water. I heard a pop which was the GFI doing it’s thing and all my outlets in the whole coach quit working but the motor still runs fine. I reset the outlet but nothing works in the coach that’s supposed to when generator is running. It has power going through the circuit breaker from the generator but nothing from the other leg of the generator ( power through M1 none through M2) I tried holding the start button over but it didn’t do anything for the M2 circuit. You think I overloaded the generator and it grounded out that side? I have 130v coming out of M1 circuit. What’s your thoughts?

  6. GMG says:

    Hire electrician for safety reasons. The generator might need to be flashed if it has been sitting or the batteries have gone bad. Check all wires (mice are a big problem), check all breakers to make sure they have not tripped. Check the main grounds.

  7. Stefan says:

    My Generator doesn’t bring in electricity in the house but the generator runs. I don’t know but I think it’s from the plug switch which has problems but what do you think it’s the problem?. Thanks

  8. GMG says:

    Try flashing. Use a multi-meter to test, never the on-board meters. Check connections, breakers. It could be a safety circuit preventing power. More serious would be bad windings, damage in the generator head or diode problems.

  9. gmg says:

    Look in manual for flashing routine. Check batteries and connections. Assuming you have an electric start unit, your voltage regulator (the one that controls battery charging) could be bad. This is separate than the VR that controls output voltages fro the generator itself.

  10. Amaro landin says:

    Have ridgid generator turns on no output, replaced the voltage regulator still no output . Any suggestions thanks

  11. gmg says:

    We have technicians in the Southern NH region only. If you are nearby, we can help. Not sure if rewinding is the most economic solution though. GMG

  12. Luke kasu says:

    I need a company which can fix my generator or recoil it since is not producing power and the engine it’s working

  13. gmg says:

    Your unit may require batteries to be operational at all times. I am not familiar with your specific generator. Not all generators can run without batteries after starting.

  14. gmg says:

    You will need to consult an electrician. Could be breakers. Could be misue of generator (i.e. too much load). The transfer switch must be rated to protect the generator from being over-taxed. If it is over-taxed, voltage can drop and destroy appliances and/or cause them to shut down if they have low-voltage safety switches.

  15. gmg says:

    Possibly need a new voltage regulator. Assume you checked with an independent voltage meter (not the on-board meters). It could be rectifier board in the distribution box.

  16. Albert Davis says:

    I have a mep003a, 1987, got it couple years ago with 13 hours on it. Never had any problems, it ran my entire house except A/C. Used it a couple months ago and it couldn’t handle my water heater, bogged the engine down, then lost all voltage and nothing on voltage or hertz meters. Tested both sides of main breaker, nothing. Please help, thanks.

  17. Edwin Colon says:

    Hi. I recently bought a Blackmax powered by Honda generator 8750/7000. It’s connected to a transfer switch in the house. Everything was working fine in the house. Today, I noticed some of the appliances work and some don’t work but the generator is running ok. It looks like voltage is coming in the house. I’m wondering if what’s causing the problem is one of the breakers. Can you please help? Thanks

  18. gmg says:

    This will require some electrical troubleshooting to isolate the problem. Could be a short. Could be a disconnect.

  19. Francisco De La Torre says:

    I have an MEP006A in which the engine runs great. However I have a similar problem to what is describe above. It generates power but only when the start switch is held up constantly. It strat to generate power instantly as soon as the start switch held in the start position but if you let the start switch go then no power. Can someone help??

  20. Than Oliver says:

    I have an old portable gen that was not producing electricity, first I put the breakers, still nothing, so then I did this trick I know about, you plug a drill into it and turn that drill with a cordless one, worked great.

  21. Rodney Poirier says:

    I hold the start switch till it runs on its own and a Lil longer it excite then it drops if u hold it it will stay but not stay

  22. gmg says:

    Could be a bad main AC circuit breaker. Have you tested the incoming voltage to the breaker to confirm that there is voltage?

  23. Bismar Lechado says:

    Im in the army the 100kw generator MEP 807A runs good but every time i closed the ac circuit interrupter there is no voltage coming out of the terminal board what it might be

  24. Rick Stuksa says:

    I have a troybilt portable generator that will not put out electricity. I have flashed the unit twice and not change. I put a meter in the receptacle and was getting 2.9 to 3.0 volts. Replaced the regulator and flashed again same results. Any idea

  25. gmg says:

    First off, you should NEVER backfeed through a 220 or dryer outlet. You can electrocute yourself or a utility worker or fry your generator. Some electrical component fried. Could be voltage regulator, could be diode or rectifier. Depends on make and model.

  26. 357storage says:

    The power came back on when my generator was running and plugged in power went in to the generator from power line ,now it will not make any power.jim

  27. shabani malamla says:

    Sory sir my generator is cummins 20kva after 30minutes engine is runing but on the lcd bord is sing warning and shutdown then after showing this no electricity provide again

  28. gmg says:

    If by half power, you mean half the voltage. You need to ensure that the unit is running at 60Hz. Must use a multi-meter and not the on-board meters to rule out bad on-board meters. 60Hz = 1800 or 3600rpm (depending on your engine). If the voltage is still half (i.e. 60 instead of 120 volt), then I would suspect a bad voltage regulator. But you will need to ensure all connections are good, no shorts, and the unit should be grounded properly.

  29. gmg says:

    First, you must use a multi-meter and not the on-board meters, which can always be bad or inaccurate. What meter are you looking at (% load or voltage)? Check manual for fuses/breakers and the method to “flash” the unit. Each unit can be different. You must have manual;-)

  30. Garfield Jenkins says:

    I have a 6kva villiars portable generator, runs great but noticed voltage gage don’t move when running only when you plug in something? Put it away after running it for hours and tried it out again and now nothing showing on meter and its no power, is there fuses anywhere or compactor? It’s running lovely but before the voltage gage went up only when I plugged something in but now nothing on gage and no power??? Strange its the villiars es model 6kva

  31. gmg says:

    Check rheostat and voltage regulator. Not sure what make/model you are having issues with, but you need the manual and you need to follow the steps to check various inputs/output voltages and readings for various circuits. You need the manual and good multi-meter. Do not depend on the meters on the panel.

  32. Jason Mukungu says:

    My dear,my generator runs well but its output is 200v. I’ve done everything even removed the exhaust thinking its giving feedback but all the same. The brush is OK,now what’s the problem?

  33. gmg says:

    We are not very familiar with the HLP 3000. Are you sure you are doing the correct flashing routine? There can be multiple. Look at manual for routine. Also, ignore the meters. You need to have a good multi-meter to rule out a bad meter. Check all ground connections from controls to frame. Wish we could offer more help!

  34. Todd Dickinson says:

    I have a HLP 3000 military 3kw diesel generator set. Started it up to make sure it was still running good as I am selling it. Started and ran great, but when I turned the a/c switch to on it showed nothing for volts or hz and no fault either. I hooked a battery to it (usually pull start it) to try the holding starter switch after its started to try to reenergize the brushes and the a/c light came on for about 2 seconds then back off again. tried this method several times but the a/c light never came back on and still reads no volts or hz. It worked fine 2 weeks ago, I don’t understand it.

  35. Jimmie says:

    Thank you, I had the same problem and holding the starter button after the engine started for a few seconds regenerated it !

  36. Jared says:

    We have an 806A that the field wont stay flashed when we release the Start switch. Even while holding to start it only reads 83 volts on multimeter and undervoltage fault comes up. Have checked all switches, VR, reconnect panel, over/under voltage relay, and the alternator diodes. Have any idea what it could possible be. Our next step would be to check the alternator.

  37. says:

    Hz meter should read 60Hz steady. This corresponds to an 1800 rpm engine which is controlled by the throttle/governor vernier/twist cable. Voltage Regulator is in the main control box (the main box with meters, switches that controls the unit). Open panel and voltage regulator is on the left wall – it is a circuit board that regulates the AC electricity generated by the unit. Check to make sure main breaker is on before testing the lug terminals (read manual for detailed testing procedure). I would love to build a network of ex military technicians. I do not know one off the top of my head in the MD area.

  38. greg says:

    Yes tried holding starter. It runs great but nothing on any gauges. Should there be something on the frequency gauge? All wiring seems right. Where is the voltage regulator? On engine like a car? Would that be just for the 24volt part or do you mean one on the gen-set?
    Thanks for the reply so far. Also I’m in Maryland are there knowledgeable people who can come and look at it out there? I mean for pay of course. Like ex military.

  39. gmg says:

    Did you try holding the starter in the start position even after unit has started? If this doesn’t work check all wiring and look at voltage regulator. I assume all breakers are on and you have checked output at lugs. GMG

  40. Greg says:

    I recently bought an 002a from Government Surplus. Starts and runs great. Says 1300 hours. The generator shows nothing though. Tried the “energizing” method with the bulbs and the drill. Still nothing. Got no flashing on the bulbs just light. Any other suggestions?

  41. Larry Pedersen says:

    Regarding flashing the field on a MEP002a. My MEP002a forces me to hold the switch in the start position, because I have to wait a few second for the oil pressure to to build to normal pressure. If I don’t wait, the engine will shut off if I release the switch too soon.
    The situation you spoke of would lead me to check the oil pressure switch for proper operation also.

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