Onan MDJF

[ldecaul]

A resistor in my generator control box overheats as soon as I turn on the battery isolation switch. This resistor is 50 watts 7:5 ohms. 4 in long sits next to a smaller variable resistor.

Anyone knows why this may happen, what causing the problem?

Onan MDJF 15kw

Kind of new here .

[Captain Ralph]

I remember a big wire wound load coil (resistor) that will burn your hand if touched.
Overheating or just very hot?

I assumed it kept the 12v glow-plugs in spec when the gen-set was started with 24 or 32 Vdc.
It may also maintain 12V on the run solenoid with 24 or 32Vdc units.

When the gen-set is running, an air flow should go over it.

Are you having problems and trouble shooting an issue or just trying to get closer with your pet dinosaur.

[ldecaul]

I am having problems troubleshooting. Replaced the water pump now having trouble starting . Can’t get past the overheating of this resistor and the crank limiter tripping. I am wondering if the LOP sender is the problem

Any help is appreciated. This resistor is in the lower part of the control box. Along with the start solenoid. Both resistors are new . Start stop solenoid new crank limiter new. Seems like the problem is on the engine side. A safety issue. Don’t get where to start.

[Captain Ralph]

Did it ever run?
Water pump replacement? Overheated?

[ldecaul]

Water pump failed. Unit shutdown as should . Replaced the water pump. And the unit ran for a short while and then shutdown again. New problem . Pump drive gear key worn. Will not engage with the pump. Long story. Fixed gear shaft key and installed it. Engine turns over and I am sure it will start once I get past the problem as described above.

Update . I removed the wire from the LOP sensor and the resistor did not get hot engine turns over.
Next step replace sensor. Part 309-0169 . Hard to find. Anyone with info? Where to , how much.

Thanks Captain for your input

[Captain Ralph]

Water pump failed. Unit shutdown as should . Replaced the water pump. And the unit ran for a short while and then shutdown again. New problem . Pump drive gear key worn. Will not engage with the pump. Long story. Fixed gear shaft key and installed it. Engine turns over and I am sure it will start once I get past the problem as described above.

Update . I removed the wire from the LOP sensor and the resistor did not get hot engine turns over.
Next step replace sensor. Part 309-0169 . Hard to find. Anyone with info? Where to , how much.

Thanks Captain for your input

I would also check the high temp switch. For it to work the first time in many, many years,,, it may have gone south.

[whoover]

Check onan parts.com it may be available there. Finding parts for old onan gen sets is a tough job, I've been there.

Walt Hoover

[ESCAPE PLAN]

Water pump failed. Unit shutdown as should . Replaced the water pump. And the unit ran for a short while and then shutdown again. New problem . Pump drive gear key worn. Will not engage with the pump. Long story. Fixed gear shaft key and installed it. Engine turns over and I am sure it will start once I get past the problem as described above.

Update . I removed the wire from the LOP sensor and the resistor did not get hot engine turns over.
Next step replace sensor. Part 309-0169 . Hard to find. Anyone with info? Where to , how much.

Thanks Captain for your input

try ESS-KAY yards marina
315-676-2711

315-676-2711
315-676-2711