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Locate Onan oil sensor switch

LI-Camper
Explorer
Explorer
I have an Onan 4kw generator on a 2004 Jayco Greyhawk. It is a 4KY type gennie. I am experiencing generator shutdown after running about 15 - 30 minutes. This is with or without load. I would like to check the oil sensor but can't find it . It does not appear to be on the right side as my diagrams indicate. Could it be in the oil pan? Besides the oil sensor my next culprit would be the fuel pump. Any suggestions would be helpful.
2016 Jayco Greyhawk 29MV
Sold 2004 Jayco 27DS MH
Wherever you go, there you are!!
10 REPLIES 10

j-d
Explorer II
Explorer II
Glad you have it running! Thanks for letting us know what worked. So often, the OP doesn't give us an update.
If God's Your Co-Pilot Move Over, jd
2003 Jayco Escapade 31A on 2002 Ford E450 V10 4R100 218" WB

LI-Camper
Explorer
Explorer
Got the new fuel pump installed this morning. The generator ran for half an hour without any issues. Thanks for all the suggestions. We leave for Niagara Falls this Sunday.
2016 Jayco Greyhawk 29MV
Sold 2004 Jayco 27DS MH
Wherever you go, there you are!!

LI-Camper
Explorer
Explorer
Thanks for all of these suggestions. When the generator quit last time after running 14 minutes, it wasn't getting any fuel. This is after replacing the fuel filter to see if that was a cause of the problem. Looks like the fuel pump is the problem. I'll report back after the pump is installed.
2016 Jayco Greyhawk 29MV
Sold 2004 Jayco 27DS MH
Wherever you go, there you are!!

Steele_Grey
Explorer
Explorer
If you recently added oil, it could be overfilled. This happened with me once when I topped off the generator and it would die after 12-15 minutes. I drained some oil out till the dipstick showed a bit below the full mark and it ran for hours without a hiccup.

_40Fan
Explorer
Explorer
It is that time of the year again. Voltage regulators are way too common.
2013 Arctic Fox 22GQ
2011 Ram 2500 CC LB CTD G56 3.42 Mineral Gray

CloudDriver
Explorer
Explorer
Had the same symptoms with our 4KY Onan a couple of years ago. Turned out to be the fuel pump.

Your generator should have a "prime" function on the start stop switch at the generator itself. When the generator shuts down by itself, hold the prime side of the switch to see if you can hear the fuel pump running. It makes a buzzing sound. No sound = new pump needed.
2003 Winnebago Minnie 24F - Ford E-450🙂

TyroneandGladys
Explorer
Explorer
We had similar issue at campground one time and it was from overheating. Left compartment door open problem solved.
Tyrone & Gladys
27' 1986 Coachmen

LI-Camper
Explorer
Explorer
Thanks, J-d. I put in a call to a Onan distributor and that's what they told me.Now I have to determine why the generator stops after running for 15 - 30 minutes.
2016 Jayco Greyhawk 29MV
Sold 2004 Jayco 27DS MH
Wherever you go, there you are!!

j-d
Explorer II
Explorer II
L-C, it's a better Tech Issues Forum question.
I don't have the details but I understand that somewhere in the evolution of the KY series, ONAN discontinued that sensor. Somebody over there (or on smokstak.com) could tell you, but you may be looking for something that's not there. It depends on the Spec Code of the generator.
If God's Your Co-Pilot Move Over, jd
2003 Jayco Escapade 31A on 2002 Ford E450 V10 4R100 218" WB

Mich_F
Explorer
Explorer
My 97 4K wouldn't skip a beat if it just sat on level ground. When I drove it on any incline or went around a corner it would die. The problem was the low oil shut off, which in my case was in the pan. My repair shop just disconnected the wire or wires from the sensor and I haven't had any problems since.
2014 Itasca Spirit 31K Class C
2016 Mazda CX5 on Acme tow dolly- 4 trips ~ 5,800 mi
Now 2017 RWD F150 with a drive shaft disconnect