Generator lurching/chugging

[desi arnaz]

have you adjusted the valves?

[NJT5047]

My Kubota did something similar while running on one of the hottest days this summer.  It suddenly wouldn't rev up.  Ended up being a sooted muffler.  Made all sorts of odd noises.  Figured big bucks.  After spending a couple days dinking with it, pulled the muffler and...
It's curious that your engine continues to run quietly between the noise peaks.  If the timing gears...pump (rack control?), cams, were the cause, seems as though it wouldn't pick back up.  Could the noise be an exhaust leak as the pressure builds up?   Have you pulled the muffler? 
Are there any large solenoids that control the RPM?  Can the speed control be mechanically operated so that the engine control is isolated from the gen head?  Could the gen head be shutting the engine down by varying the control voltage?  Isuzu diesels are good engines.  Hard to believe the engine is failing at 50 hours?   
Large MH diesel gensets are famous for sooting up small mufflers.
Good luck!
My SWAG for the day.  JR



 

[TomC]

NJT5047 makes a very valid point.  Normal car mufflers are made for Gasoline engines-meaning their passages or holes are small.  This leads to the Diesel soot blocking the small passages and eventually plugging up the muffler.  Whereas Diesel designed mufflers have holes and passages that are large enough to pass the soot through.  Good Luck, TomC

[Depewtee]

I am still waiting for a return call from the Ideal Marine Diesel - the closest authorized repair center.  When I spoke with them originally they said they might have a service technician in the area within the next two weeks.  The muffler is designed for the engine, but I will try some of the suggestions made in this thread and report back this weekend.

Thanks to all,
Brian S.