EF2400is revs high & no A/C power

[StevenWells]

I have the EF2400is.  After running the generator on my travel trailer for fourteen hours, I noticed the engine rev up well above normal when I removed the load before refueling.  The engine also ran too fast after I re-started it, but when I re-applied the load it seemed to run fine.  I again noticed this during the next two refuelings.  Approximately 20 hours after I first noticed the erratic behavior, the engine began changing speed under load, mostly faster than normal, sometimes slower than normal.  This caused the generator to go into overload and the engine ran very fast in this overload condition.  Past experience has shown that the engine should run at idle when in overload.  Now the generator mostly runs way too fast under no load and sometimes runs too slow and does not produce the correct power.  The AC power indicator light (green) flashes on periodically but mostly says off.  
I've cleaned the carb jets, spark plug, and spark arrestor and there were no signs of any problems, although I noticed that the dealer did not replace the bolt in the air cleaner case from previous work.  I had the cylinder head replaced in the Spring of this year under warranty because the valves would not stay in adjustment.  I had less than 15 hours on it since the replacement before this weekend.  Any ideas?  I'm guessing it's either the speed limiter assembly or the TCI unit.  Does anyone have any troubleshooting techniques?  Thanks in advance for any help.

[CycleRob]

StevenWells wrote:

I first noticed the erratic behavior, the engine began changing speed under load, mostly faster than normal, sometimes slower than normal.  This caused the generator to go into overload and the engine ran very fast in this overload condition . . . . . Now the generator mostly runs way too fast under no load and sometimes runs too slow and does not produce the correct power.  The AC power indicator light (green) flashes on periodically but mostly stays off.   

Steven, After the dealer tech put it back together for the rebuild, it's very likely a critical wire or connector has come loose and is short circuiting. The flashing green lite, a HUGE "red flag", shows the controller may be loosing the true voltage/current load signals it needs to properly control the engine RPM's. I would not run the engine again until the wiring is closely checked out, as a short circuit can damage the (!expensive!) controller. If you can do this yourself, cool. Otherwise, a call to the repairing dealer with the possible flaws I mentioned should raise serious doubts in his conscience about the work his tech performed. He may be willing to give it a free/inexpensive checkup to set things straight.

Good luck!

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[StevenWells]

Thanks for the reply.  I took the generator to the dealer and they said the problem was the spark plug (this was about the only thing I didn't check that I knew how to before I took it in.  I knew the spark plug didn't have many hours on it so I skipped it).  The dealer said they found nothing else wrong.  After that I ran it on my RV one weeked (approx. 40 hours) and it worked fine.  I haven't had the opportunity to run it much since.  I looked for a loose wire before I took it to the dealer, but found nothing.  It was hard to believe that the spark plug would cause those symptoms.  Hopefully it was only the spark plug, but time will tell.  I've had numerous problems with the generator over the 2.5 years I've owned it and I wonder if a loose connection somewhere is the real cause of some of them.  I still like the power vs weight with low noise that the generator provides, but wish my reliability was as good as others seem to have.