MEP 803A Surging, Not holding frequency

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Conatus

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I have a MEP 803A that is new to me. it starts right up and while it's cold runs great, once it warms up the frequency won't hold steady. i shot a video showing this. it is very long but it is one cut from start up to shut down. Any help would be appreciated. If you are reading this directly after me posting just be patient on the video as it is currently being uploaded.

https://youtu.be/L5zpAkrUWp0
 

Ray70

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Hello, Have you done any service on the machine? Fuel filters, oil etc? and have you tested it under a load?
I'd be curious to see if the frequency swing starts sooner and is more pronounced when under a load.
My first thought is a fuel supply issue which will probably be exaggerated if you test under a load.
Also, make sure the fuel cap vent ( on the inside of the cap is open and not in the closed position.
 

kloppk

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To me it seems to be a fuel delivery problem. Starts to starve, RPM's drop, gets fuel again and over revs causing Hz to drop and then go high.
Possibilities in my mind are...
- Failing primary fuel pump?
- Crap in the tank randomly clogging fuel pickup?
- Clogged fuel filter on the primary fuel pump?
- Clogged primary and/or secondary fuel filters?
- Water in fuel water separator?
 

jamawieb

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I agree sounds like fuel delivery. Fuel pump not able to deliver enough fuel, filters clogged or something blocking the fuel pickup in the tank.
 

Chainbreaker

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Inverted cone inside fuel cap has 'OPEN' and 'CLOSED' stamped on it. Point the small cross bar at 'OPEN'.
Often the fuel cap is the first thing to get rusted on the inside making it difficult or impossible to read the "Open/Close" markings. Sometimes you can take a pocket knife, or what have you, and scrape the rust off and read it but the rust usually comes back fairly quickly. Regardless, I always know that it is in the "Open" position if I can pull on the center of the tab and the spring underneath allows it to travel up just a bit. If its tight feeling when you pull up on it, its in the "Closed" position. Another way to know is that in "Open" it allows the crosswise piece to fall into the lower most indentation in underside of cap with the help of the little spring holding it up. Think of it as having a sealing gasket on top of a small hole and when its pulled down tight its "Closed" since the underneath tab is in the raised position on the cam keeping it tight .
 

Guyfang

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OK. Let clarify what we saw with the clip. I watched it 5 times. The gen set ran with no load, most of the clip? Or did it have a load the whole time? Or you put it on load, and then it started hunting? Or with no load, after warm up, it started to hunt? What I do see is you pulling the plug out, and sticking it back in, under load. That WILL cause it to hunt. And its not good for the plug, nor 120 volt outlet. Try that at night, and you will see a great big fat arc. Also noted, your percent of rated load meter is not reading. What position do you have S8 in? Because S6 control what you should see on the meter. They have to be in the same ball park, so to speak. The reason I want to see what the % rated load is, so we can see just how big your load is.
 

Bmxenbrett

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I had a surging 802 before. If i remember right there was a plunger that was stuck on the injection pump. You could also try adjusting them as per the TM.

Of corse all of this should be after lunricated new fuel is put in and the fuel filters changed.
 

Conatus

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found a large 240v 10kw heater that took it up to 75% load on the gauge. frequency drooped a good bit but held steady, only thing disconcerting was the embers and blue smoke that came out of the exhaust.
 

FloridaAKM

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The embers & blue smoke are carbon & unburnt diesel residue burning off the combustion chamber, valves & exhaust manifold. The more you run it under load, the better the engine will run as it cleans out the wet stacking that diesel gensets get from being underloaded & run for periods of time. Running it under a load like that is good for diesel gensets. Removed the rest of the post due to the genset is an 803, not an 802.
found a large 240v 10kw heater that took it up to 75% load on the gauge. frequency drooped a good bit but held steady, only thing disconcerting was the embers and blue smoke that came out of the exhaust.
 
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Conatus

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@floridaAKM it is rated at 10kw at 0.8 power factor which means it is 12kva a heater is a resistive load which means 10kw is the same as 10 kva. the heater is also single or 3 phase and i didn't check how it was wired i only assumed based on where it was run last and it is very old. i say that to say there could be a big difference between the 10kw on the tag and what it actually pulls.
 

Conatus

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Guyfang
Originally Posted by Conatus
found a large 240v 10kw heater that took it up to 75% load on the gauge. frequency drooped a good bit but held steady, only thing disconcerting was the embers and blue smoke that came out of the exhaust.
where did you hook this up. Load terminals, or 120 volt outlet.



Terminal lugs

Coug
Originally Posted by Guyfang
where did you hook this up. Load terminals, or 120 volt outlet.
is it even possible to hook a 10KW 240V load to the 120 outlet?






You could try but it wouldn't end well.

i tried again today. ran the 11 amp heater for a while with no problems, but once i connected the big heater it surged quite a bit.
https://youtu.be/9f4OimbGGk0
 

Guyfang

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Terminal lugs



You could try but it wouldn't end well.
That's why I asked. And yes, I could. Just have to move a few wires.
I don't know what you know, so got to ask. If your using a 10 Kw load, and turning it on and off, that will make it hunt. And if the set is wet stacked, it can hunt. That's why I asked you those questions in post #8. How does it run at 5KW?. You see, everyone is wrapped up around the axle about full load, but no one thinks about 1/4 or 1/2 load. Will it run right at 2 KW? At 4 KW. Throwing a full load at a set is unrealistic. Give the thing a chance. Step it up to a full load. Start at 2 KW. Run it an hour. Bump it up to 4 KW, run it an hour. Do you see lots of carbon coming out of the exhaust? Smoke? Will the load settle out? Still hunt? Test it in a logical manner. Not just drop huge loads on it.


i tried again today. ran the 11 amp heater for a while with no problems, but once i connected the big heater it surged quite a bit.
https://youtu.be/9f4OimbGGk0
,
 

Conatus

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Central PA
That's why I asked. And yes, I could. Just have to move a few wires.
I don't know what you know, so got to ask. If your using a 10 Kw load, and turning it on and off, that will make it hunt. And if the set is wet stacked, it can hunt. That's why I asked you those questions in post #8. How does it run at 5KW?. You see, everyone is wrapped up around the axle about full load, but no one thinks about 1/4 or 1/2 load. Will it run right at 2 KW? At 4 KW. Throwing a full load at a set is unrealistic. Give the thing a chance. Step it up to a full load. Start at 2 KW. Run it an hour. Bump it up to 4 KW, run it an hour. Do you see lots of carbon coming out of the exhaust? Smoke? Will the load settle out? Still hunt? Test it in a logical manner. Not just drop huge loads on it.
finding Things to put on as a load is difficult for me. at 2:50 in the video i show the black specks that are coming out of the exhaust
https://youtu.be/9f4OimbGGk0?t=229
 

Conatus

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Central PA
something i wanted to explore was the droop adjustment in the manual. Do you think this could have anything to do with what i am experiencing.
Droop Adjustment.jpg
 
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