Help

[Rich Biebel]

Dan and Bill are correct...

Matt is a comedian but also a pretty dern good S/G racer...LOL..... and we have worked together for over 20 years for RJ Control Inc...

Bill is also correct.....brushes are the first thing to check on a 4KY
It is not hard for me but I do them all the time.

An ohmmeter across 2 pins that connect the brushes to the controls is the first test to do. A good reading should be around 20-25 ohms and it should not change when you slowly turn it by hand at the blower wheel..

The brushes are under the blower wheel and take a lot of work to get to.

Just did one yesterday for a racer and his unit is good to go again and coming back out to Maple Grove tomorrow night..

4KY's don't have an oil pump so they have no low oil pressure switch.
They rely on splash oil.
The older ones do have an oil level switch and they sometimes cause shut downs but usually only after the unit runs for a long time.
They did away with that switch......If you run low on oil your engine will break a rod......aluminum rod, no bearing...

Cummins owns Onan.....Onan was never shy about their parts prices and prices have risen considerably since Cummins took over.

Matt and I both will be at the Dutch....
Truthfully.....I hate working on generators at the track when I am trying to race......I hide....LOL
Matt likes it and was all over the place last weekend diagnosing issues for everyone from NHRA on down the line.
Making major repairs at the track is usually pretty difficult....

[Bob Bender]

Input a new pump on 2 yes I got from Matt at Cecil. I put in a new batt. It went dead. Changed the fuel filter. Now its not pulling fuel through the filter. Ran great last night.

[Bob Bender]

32 code

[Rich Biebel]

How many hours on it ?

Code 32 points to something that is usually not whats wrong with it from my experience..


Push the start/stop switch to the stop side....that is also Prime when the engine is off. FuelPump should run. Pull line off where it attaches to carb and with switch on stop/prime.....pump fuel into a small bottle. Verifys pump is working and you have fuel in the carb.

If you have fuel and it starts but shuts off when you remove your finger from the switch you probably have lost AC output on that unit...and as I said brush condition/connection is the first place to do some testing.

You have to disconnect the battery + from the solenoid and tape it up so you don't do any 12 volt welding....LOL or start a fire.....

You need to remove the plate where the solenoid is mounted.
It's a struggle but that all comes out with the ECU or control underneath it.



It has one weatherpack style connector. Release the lock.....pull the plug out....

Pins #1 and #10 on the connector will be from the brushes.....
The wires are all white....and printed right on them
F- and F+
An ohmmeter with stab probes into the connector at those 2 positions should show you about 20-24 ohms.....and as I said if you reach in and rotate the blower wheel by hand.....that reading should not fade or go high.

If you get good readings your problem may be the controller (PC Board) or something more serious like a stator or even the rotor....

Ohm readings help but don't always tell you whats wrong.
Often they need to be disassembled to visualy find the problem....


An Onan needs a battery connected to it to run......If it is good enough to crank it, it is good enough for it to stay running.

Battery going dead is a separate issue not related to it "won't stay running"
4KY's have no battery charging built in.
A separate charger or converter is necessary to charge your "house" or starting battery.
M-H's generally have a DC converter and they charge the battery as well as run your DC items in the M-H...mostly lights and vent fans...

I have a 4 KY in my trailer. I have a small 6 amp Battery Charger that charges my battery when the generator is running....