MEP-803A Troubleshooting Assistance Needed

Ridgerunr

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Camp Hill/PA
Greetings all, I’m having operating issues with my new (to me) MEP-803A. It’s a 2010 unit with 10 hours on it. I picked it up from GL at Tobyhanna PA back in September. They had video of it running with the info on their site.

To this point I’ve done the following maintenance:
Changed the oil & filter. Had about a cup of water in the oil, believe due to the exhaust cover having been removed and the opening covered with duct tape. Still a bit of water in the crank case so I’ll be changing it again shortly. Will be switching to break-in oil once I get all the water out.
Drained, flushed, and refilled the cooling system. (what was drained looked clean and good)

Changed the fuel filter. And bled the lines IAW the engine manual. Haven’t gotten the oil/water separator off yet but have a new one ready. (Broke my strap wrench trying to turn it)

Replaced the fuel return lines from the injector pump manifold and over the top of the motor. The section going back to the fuel tank was replaced previously and is in good condition.

(Thank you to member Daybreak for his fantastic documentation of the fuel return line and all the filters, parts etc.) It made this maintenance much easier for a new generator owner!

The generator starts right up but will not achieve a stable RPM speed. It surges up, then slows down constantly with the frequency fluctuating from below 50Hz to 60 then back down again. Adjusting the frequency control does not seem to help. It will run like this for about five minutes then gradually slows down like it is fuel starved. It then won't start for about an hour or so. Then the same thing happens again.

I’m trying to attach a video of it running so you can hear what it is doing, but it's not working.
Link to the video on YouTube:https://www.youtube.com/watch?v=AgTB9af2bEw

Any help of advice you can provide would be greatly appreciated. I’m just not sure what to try next.
 
Last edited:

Kemp3

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Carmel Valley
Check your governor , sounds like lean hunting to me .

maybe manually open and close it a few times , same goes for the throttle on top ( linkage from the frequency knob hooks up to it )

Best of luck

-Kemp
 

DieselAddict

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Do you have a good steady flow in the return line to the tank with the fuel pump running?

It sounds to me like its starved for fuel.
 

Daybreak

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Howdy,
Finish the job of getting it ready to run. Get the fuel/water spin on filter replaced. Get the tank cleaned out. Get some fresh fuel in there with some additives. Prime it a good long time to fill the fuel filter cartridge and spin-on fuel/water filter. Double check the fuel cartridge filter cup. Did it mate up to the top along the seam all the way around? Is the little rubber gasket in place?

The fuel/water spin-on filter is really a bear to get off. Every single one I have taken off, I have totally destroyed the filter. It seems the filters were put on dry by King Kong.
 

Ridgerunr

New member
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Location
Camp Hill/PA
Latest Update

Replaced the fuel/water separator (new filter wrench & PB-Blaster did the trick)
Drained the fuel tank and cleaned the inside as best as I could. (Very little dirt, no crud) refilled and added fuel treatment.
I did not observe any water in the fuel I removed from the tank. It looks/smells ok.
Bled air from the fuel system IAW the engine manual.

When I first started it up after the maintenance, it ran smoothly for about 45 seconds before beginning the surging again. Runs like that for about 5 minutes before slowing down and stalling. After it does this, it won’t restart unless I let it sit for about 30 minutes before starting again.
I removed the hose from the fuel return manifold and with the fuel pump running had a steady stream of fuel coming out.

What drives me crazy is that GL had a video of it running good on the sale page and when I get it home and gone over, have this problem.
I’m really at a loss on what to try next. Was thinking of maybe trying another fuel pump or pulling the injectors and getting them tested.
 

armyrino

Member
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Location
Jacksonville Florida
Sounds like fuel starving, and or vapor locking. Check to make sure your fuel supply lines and return lines are correct and free. Could also be air in the lines. Check for fuel supply leaks . The smallest leak will do this. Did you bleed all injectors once you changed all the lines?
 

jamawieb

Well-known member
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Location
Ripley/TN
Latest Update

Replaced the fuel/water separator (new filter wrench & PB-Blaster did the trick)
Drained the fuel tank and cleaned the inside as best as I could. (Very little dirt, no crud) refilled and added fuel treatment.
I did not observe any water in the fuel I removed from the tank. It looks/smells ok.
Bled air from the fuel system IAW the engine manual.

When I first started it up after the maintenance, it ran smoothly for about 45 seconds before beginning the surging again. Runs like that for about 5 minutes before slowing down and stalling. After it does this, it won’t restart unless I let it sit for about 30 minutes before starting again.
I removed the hose from the fuel return manifold and with the fuel pump running had a steady stream of fuel coming out.

What drives me crazy is that GL had a video of it running good on the sale page and when I get it home and gone over, have this problem.
I’m really at a loss on what to try next. Was thinking of maybe trying another fuel pump or pulling the injectors and getting them tested.
I just finished working on a 803a that would start perfect and run about 3 minutes, then start missing, with it finally stalling. I couldn't restart for at least 1 hour. I thought it was the fuel pump so I replaced that, still had the same issue. I took the fuel line off at the fuel pump coming from the tank and tried to blow into it and couldn't, I knew then I had a blockage! So I reached my hand into the tank and found the pickup tube and pulled a big glob of what looked like wet fiberglass out of the pick up tube. Mind you, when I received the generator, I drained the fluids and wiped the tank clean so I don't know what the foreign matter was.
 

Guyfang

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NEVER trust anyone but yourself, and double check him! I had a problem like that with a piece of plastic. It would float around, get sucked up, cut off fuel, set dies, plastic dropped off fuel pickup. Started all over again. Glad you got it fixed!!!!!!!!!!!!!
 
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