Last Saturday at College Station, fired up the generator with a light load when shut the bus down. It started up right away, but soon began shaking and causing the lights to flicker. Since it was cooler than I had ever started the genset before, I assumed it might need to warm up a little. Shut it down and re-started several times with same result. It would run fairly smooth for a few seonds and then began shaking. Ended up shutting it down and leaving it alone until I returned home.
Sunday afternoon I started it up at the barn to check things out. It started shaking again, so I kicked off the load switch which caused it to smooth out. After it ran for a few minutes and came up to temperature, I switched the load back on and it ran fine. Ran it for 2 hrs while doing some other work around the coach with no problems.
Tonight I went out there to do some work on the coach. Pulled it out and fired up the genset. started shaking and causing voltage surges and flickering. Generator output voltage varied wildly on the Trace display 100 to 145 volts. This time it wouldn't smooth out when loaded even after it was warmed up. Never could get it to stop shaking when I flipped on the load switch.
Initially thought it might be a fuel problem, then thought it might be a temperature problem and now am wondering if it is a voltage regulator or something like that (Leon at Marathon suggested contacting Detroit/Kohler but guessed voltage regulator)? When unloaded, it still shakes a very small amount - once it is loaded it starts to vibrate after a few seconds and almost gets into a harmonic type of action.
Ideas? Tomorrow I am going to change out the fuel filter. I keep thinking it is sourced on the generator end, but with the slight amount of shaking, still wonder if it is in the motor and then gets magnified when loaded (not big loads here either 10-15amps)?
Kohler 20KW with 3200 hrs.