MEP-803 - Fluctuations in Hz - Puerto Rico - HELP!!

[gonzo119]

A 10kw-Onan-DN4M / LP460, currently has 30 hours of use. Starts up on the first try, however after running for several mins the engine begins to rev up and down, the only gauge that moves is the Hz gauge which swings back and forth over 60hz. This happens whether on or off load. Any input, advice or suggestions would be GREATLY appreciated!! I am located in Puerto Rico and a generator is a necessity here right now with very few people to service them.

Thank you!!
PhillipView attachment MEP803HZ.mov

 

[DieselAddict]

How long have you let it run?

How much swing does it have?

 

[gonzo119]

The first 2 times I let it run for about 15 mins and then the fluctuations began. After that I have started it several time and about 5 mins later the Hz will start to swing. With 55hz being the lowest and 65 the highest, the dial will sing anywhere between 1/4 to 3/4. I have a short video of it however it is 20mb and I am not able to upload it.
I really appreciate your response.

 

[gonzo119]

I believe the video was uploaded.
MEP803HZ.mov​

 

[Suprman]

Did you drain all the old fuel and put fresh fuel in? How do all the fuel lines look? Can you see any cracks? If so they need to be replaced.

 

[gonzo119]

Thank you! I just looked through the lines and believe that the return fuel line is actually cut. I'm going to start replacing it now. Do you believe this would more than likely cause the fluctuations? Thank you for pointing this out. I have had a crash course in generator over the last several days.
Many thanks!!

 

[Zed254]

4. ENGINE RUNS ERRATICALLY OR STALLS FREQUENTLY.
Step 1. Check for obstruction in fuel line(s).
a. If fuel lines are not obstructed, do Step 2.
b. If obstructed, unblock or replace fuel line(s), paragraph 2-80.
Step 2. Check for blocked exhaust pipe or muffler.
a. If exhaust pipe and muffler are not blocked, do Step 3.
b. If blocked, unblock or replace muffler, paragraph 2-65.
Step 3. Check for contaminated or incorrect grade of fuel.
a. If contaminated or incorrect grade, drain fuel tank. Replace fuel filter/water separator element, paragraph
2–87. Service fuel tank with clean fuel of a proper grade (TABLE 2–2). Prime engine fuel system
in accordance with TM 9-2815-253-24.
b. If fuel is not contaminated or incorrect grade and trouble persists, notify next higher level of maintenance.

....from https://www.google.com/url?q=https:...5:1751224275&usg=AOvVaw1yNpqr4HorII0jxHj5vvzY

 

[jamawieb]

Yes it would. Looks like the return line was leaking up top and they bypassed it. That line should go to the injectors and the force of the pump pushes the excess fluid from the injectors back to the tank. The excess fuel from the injectors is not being pushed out of the return lines so your injectors are not able to get rid of that fuel.

 

[Light in the Dark]

Silly question... what kind of power are you trying to get out of this machine? Single phase, or three phase? Also what voltage are you looking for? I ask because of your voltage settings in the video. I wonder if you don't have this machine hooked up properly, compared to what you WANT it to produce... and the machine is trying like **** to compensate. The voltage reconnection switch inside of the control console... what is that set to?

 

[AlexV]

If you have extra fuel filters I would change the filters.

 

[Daybreak]

A 10kw-Onan-DN4M / LP460, currently has 30 hours of use. Starts up on the first try, however after running for several mins the engine begins to rev up and down, the only gauge that moves is the Hz gauge which swings back and forth over 60hz. This happens whether on or off load. Any input, advice or suggestions would be GREATLY appreciated!! I am located in Puerto Rico and a generator is a necessity here right now with very few people to service them.

Thank you!!
Phillip

Howdy,
You have come to the right forums.

I know parts and pieces might be hard to come by.

You can start here. MEP-802/803 Filters and Parts The 2nd post has quick links to a lot of stuff. A little farther is the post with quick links to the TM's which you will need.

TIP: Turn the S-1 to Prime & Run for 5 minutes to ensure your fuel system is filled. The pump will run and fill the filters, and then put the excess back into the tank through the fuel return lines. After you fix them of course.

The fuel return line is 3.5mm I.D. Same as VW, Mercedes fuel return line Yellow stripe. MEP-8xx Fuel return lines

At least you can reach out with the internet.

Good luck. Post up any other issues. I am sure we can get you working.

MEP-8xx start-up routine You obviously know how to start it, but look at the single phase 120/240 selection behind the control panel. ONLY MOVE WHEN NOT RUNNING!!!

 

[TheAlfredo]

Last week I was dealing with the same exact problem on mine. And then it wouldn't restart when warm.

I literally let let it run for a couple hours and it fixed itself. I was told on here it was probably air in the lines and filters. I found it strange it was only an issue when engine was hot. But worked fine the last 3 times I cranked it. Next step is get it hooked up to the house.