Generator Notes and Projects

The boat's generator is a 1990 8KW Onan Diesel generator, which had failed long before I bought the boat.  The previous owner had made a serious attempt to get the generator working again, but finally gave up in the typical frustration of "expert generator mechanics" swapping parts, spending excessive amounts of money, and ended up with a result that was worse than the original problem...

The survey reported that the generator would start, but would not continue to run unless the stop solenoid was held open.

Generator notes:

1990 Onan Model#8MDKDB 1C 

Rated at 8 KW at 1800 RPM's and 60 Hertz 

Rated at 66.7 amps.

Kabota 3 Cylinder motor.  

The survey reported that the hours (~100) on the generator hour meter were not correct.

Repair Attempt - Linn, Advanced Marine

12-9-22

Linn from Advanced Marine arrived to diagnose and repair the generator.  First date was a very brief diagnosis - which was surprisingly positive.  Linn confirmed what the survey had said:  He was able to manually override the fuel stop solenoid (hold it open) and get the generator to start and run.  Generator would immediately shut down after starting if the solenoid was not held open.  Linn also verified that once running, voltage was generated.

Observations included:

• New control board, new fuel solenoid, new oil pressure sensor installed.

• Remote panel harness had been disconnected (some generators sense his, and will shut down without the remote panel unless a jumper is connected - this does not appear to be the case with the Onan).

• Harness had blown 30A fuse.   (Replacing the fuse did not help anything.)

• Water pump was weeping - needs to be replaced / rebuilt.

• Saltwater is in the bottom of the tray.  This may be coming from cooling system or heat exchanger?

1-4-23

Linn from Advanced Marine returned.  CB-12 (emergency stop circuit breaker) seems to be kicking in within a few seconds of start.  Linn checked all the sensors feeding the shutdown relay.  They all appear to be functioning properly.

1-27-23

Linn returned.  Replaced CB-12 circuit breaker (I had ordered a replacement from Elite Diesel, ~$46).  Didn't help.

2-2-23

Paid Advanced Marine $649.50.   Generator still does not run.  Remote harness is not connected.  No understanding of why control board is tripping CB-12 shutdown circuit breaker.

2-17-23

Flight Systems (manufacturer of the replacement generator control board) reorted that the board passed all their system tests.  Board returned UPS.

Check:   The survey noted that the Generator battery switch was secured to the starboard battery box.   ??   Check this!