Onan MDJA 3.0 Generator

[rossjo]

My 70's vintage Onan MDJA 3.0 diesel generator was running fine (in my boat). One afternoon last Spring (cool day) it was running, and suddenly just quit. It will start fine, but dies as soon as the start swith is released and goes back to the run position.

I've bought manuals, etc. but am still stumped. The Oil pressure, temp sensor, decompression relay, decompression solenoid, etc. have been tested (per manual) or bypassed (one at a time) to verify whether they are the cause. I have also removed and tested (or replaced) most of the wiring. I still cannot find the problem.

The "Reverse Current Relay" seems weak, as voltage will not pull in the solenoid, but will hold it there if the solenoid is pushed in while voltage is applied. Could this be the problem?

The "Flicker Resistor"is a bot of a mystery to me - could it be bad?

The adjustable Resistor for the charging circuit is about 2.6 ohms.

I have wired 12V directly to the decompression valve, and applied it afer it starts. This keeps the motor running, but then no AC voltage shows on the guages.

If I hold the start/run/stop switch in the "start" position after it strats (for a few seconds), I do see voltage (albeit reduced) and the engines runs at lower RPM (probably half of the rated 1800RPM).

We'd like to go for a cruise over Thanksgiving, and the generator would be nice for heat and Fridge (plus recharging batteries). I would really appreciate anyones help (and will take anyone fishing in Charleston, SC when they come!).

Feel free to answer here or eMail me.

[davidsmith]

Ross, You get your generator running?