Onan MDJE 7.5 question

[cpp]

While travelling back from Charleston to Wilmington last week, my generator shut down, and will not start back. It will start, but shuts down as soon as I let off start switch. I had noticed prior to it shutting down, that it was leaving black soot on the side of my boat. Also it was not putting out
full voltage prior to shutting down. Not sure if this is all related. Trying to give as much information as possible. I feel as it is fuel related. Any info would be greatly appreciated. Chris Puryear '78 37C

 

[Top Hatt Craig]

Assuming there's enough oil in it, jumper across the low oil pressure cut-out switch to if that's the cause.

 

[cpp]

H
I Craig,
Are you referring to the reset switch.? It was low on oil when it shut down

 

[Top Hatt Craig]

HI Craig,Are you referring to the reset switch.? It was low on oil when it shut down

Welcoming input from the more experienced here, there's a pressure operated switch that makes a circuit allowing fuel to flow, when there's enough oil pressure to trip the switch. If you can get it to start with a jumper across the two terminals on the switch, the switch may be faulty OR there is not enough oil pressure to trip the switch. Checking the oil pressure with a manual gauge in place of the oil pressure switch would be next if it starts with the jumper. There's also a coolant over-temp switch that would be another thing to check. When cranking does sound like it always has? Or is there a new rhythmic unevenness as in one cylinder having significantly less compression than the other?

 

[Fish Tales]

That Onan will also shut down on low voltage or low frequency. If you were sooting, and dropping voltage, check fuel filter.

When holding start switch in you are bypassing all safety's. This allows the unit to run long enough to use meter and check voltage, and frequency. If neither, gen will shut down when start switch is released. If voltage and frequency are stable, and gen stops when start switch is released, then look at other safety's. Low oil, high temp, no water flow. etc.

 

[whoover]

Hello, you can also try lifting up on the fuel shut off solenoid when you are cranking with the start switch on the unit. If it starts running then the reason it won't start is likely that it's not cranking fast enough to close the contacts that completes the circut to keep the fuel shut off in the raised position or the solenoid is faulty. A fuel filter change may be necessary. I hope this is of help, I have an ongoing battle with my mdje and right now it's winning but I'm not giving in.

Walt Hoover