diesel engine

Check if there is air lock of air leakage in fuel supply line up to fuel pump inlet manfold. I had bad expereince of air lock.

thanks for ur suggestion, it would be power up during work.

Have not adjusted a govener myself or had personal experiance of your problem, but would suggest checking the dwell in the control system, should be adjustable.

Regards JD.

thank you very much for your suggestion.

Thank you for your acknowledgement, reading further you seem quite knowledgeable and polite, I agree it could possibly be a mechanical fine fuel adjustment?

Regards JD.

I would consider having the governor rebuilt I had very serious problems on a Cummings that completely went away after a $200 professional rebuild .

If there is a possible leakage in the fuel system it might be located with soapy water spray or by blowing smoke in assembly to reveal leaks .

Try the rebuild it's cheap and will isolate possibilities unless other tests reveal a simpler problem .

Good luck!!

It sounds as though the control system action is too lively. Try reducing the system 'gain'.

you r right about the gain but i have aslo tried it many times and the result is same.

The same governor works really well on other dg set but not for this dg.

I suggest you have amechanical problem, either too light a load/flywheel or a harmonic instablility between motor and generator. In effect they are both the same if the load is too light the hysterisis effects will cause the throttle to continually raise the speed then lower it as it overspeeds due to the flywheel/load harmonic adding to the increased throttle, then as the throttle backs off the other side of the wave simultaneously tries to slow down the engine. this process always requires significant load before it irons out. I suggest adding some weight to the 'flywheel' END

If you are reasonably sure that the governor itself is OK, and assuming that there is nothing loose in the flywheel coupling , I would suggest that its a fuel starvation problem. The changing of filters is only part of the problem if you have had (a) fuel contamination, what we call "a diesel Bug" in the fuel tank, or (b) the fuel return line is connected to the input side of the fuel filters .

(a) has been discussed many times on this forum. Should be OK if you have a clean and clear sight glass under the filter/s. Not all black looking.

(b) is a common basic fault, and what happens if you get a very slight leak on the fuel suction side? where does the entrapped air go...back around..and around...and. If this is the case, simply have the return fuel go into a large bucket and your problem might simply go away. Don't leave the bucket though as depending on the type of fuel system, it will fill quickly. The correct design is for the fuel return line to go to the top of the fuel tank (then of course, find and rectify the suction side leak which may only appear when the set is running). Good luck, keep us all posted. If this no good we can try plan B.

Gee I'm glad I don't have to work on these things any more !!

You wrote: 380 kva capacity of diesel engine

I guess you mean Diesel engine generator.

If so it is the governor. maybe not the card, but the governor itself. Especially if the hunting is sinusoidal. A good way to prove it, is to disconnect all loads. If it still hunts, eureka! IT is the governor. If it doesn't than it is most probably something in the sensing system, maybe the card is the culprit or some other other component. It is difficult to tell you without knowing what type of speed control your system uses.

Wangito.

By the way I was thinking I used your term (governor)

I was referring to the injector pump rebuild as a cause I assumed other areas may call an injector pump the same .

I usually refer to a governor as a gasoline motor application .

A Governor is a governor, An injection pump is an injection pump. Two totally different animals.

1. The governor is practically speaking, an automatic throttle, It will keep a predetermined engine RPM constant, under varying load conditions.
2. Injection pump, or fuel pump will inject fuel on demand or in a constant flow into the fuel divider fuel servo or directly into the fuel injectors.

Wangito.

Then he injector pump contains a governor

I would go back to my original suggestion have the assembly rebuilt it worked for me .