OT - RV Onan Generator

johndeere720GA · Mar 1, 2014

I am having an odd problem with my Onan Generator. It has been fairly trouble free as long as I exercise it every month. This month it starts as usual then it died and would not restart. I pulled the dipstick and it was at the low mark. I thought that was odd but I went to the shop to get some oil, figuring it was the low oil cut off that was stopping the engine from running. Well I left the dipstick unscrewed while I was getting the oil and what do I find when I get back? The stick now shows it is full. The engine started just fine but I shut it off after a few seconds so I could ask you all what you think is going on. BTW I pulled the dipstick right after turning it off and it was low again but not as low as before.
So where is all the oil hiding?

bo · Mar 1, 2014

It can only leak out and you'd soon see the mess or you're burning it but not enough to see the blue exhaust and it's getting past the oil control ring. It can't evaporate.

johndeere720GA · Mar 1, 2014

No I agree it can't evaporate, but in this case it would also have to condense, for it to show full when I returned with the oil.
I didn't add any oil to it I just left the dipstick loose (screw down). It is almost like it is getting an air bubble and it is keeping the oil from the oil level sensor as well as from showing on the dipstick.

Roger in Iowa · Mar 1, 2014

Does it have overhead valves? May be not draining back out of the valve cover area. Sludged up??

1970-1655 · Mar 1, 2014

What weight of oil? How many hours on the oil? What temperature is it? (heated garage vs -20) Oil could be too thick to drain back very quick so it shuts off from the low oil sensor. Then you let it sit for a few minutes while you get more oil. That gave it time to drain back down, showing full on the dipstick again.

I had the same issue in January when the temperature in the unheated garage was about 10 degrees. I have summer weight oil in it. I change before putting it away for the winter and use the same oil I plan to run in the summer.

jm. · Mar 1, 2014

Pretty simple cold oil too thick. when you start it the oil is pumped to top of engine and will not drain back fast enough so it shuts off. After several cycles of that you probably got it warmed up enough to flow and run.

johndeere720GA · Mar 1, 2014

Thanks for all the replies. Thick oil could be the issue although it is warm here today at about 60*. It is probably due for an oil change anyway so I will do that and see what happens then. I will monitor it closely.
I just thought it was odd that it didn't flow back until I removed the dipstick then it happened quickly.

johndeere720GA · Mar 1, 2014

I guess it could be sludge but the engine only had a little over a hundred hours on it. I am going to change the oil then give it a try. May not make it this week but soon.

Billy Shafer · Mar 1, 2014

Depending on what you have. The oil can be slow to drain back.Nothing to worry about. Just let oit sit a little longer before you check the oil.

Onan tech since 1980.

wilson ind · Mar 1, 2014

pull dipstick creates an air vent.

Bob · Mar 2, 2014

Using a DEERE 318 as an example (Onan engine) the dipstick tube is not vented, and is (at the bottom) below oil level, meaning that when the dipstick is first pulled, the level of oil on it has NO bearing to the actual engine crankcase oil level.

Pull the dipstick, wipe it off, and take a couple of minutes to enjoy the weather/scenery, then re-insert it and see what the oil level REALLY is.

Bottom line is, in yoir case, the oil was not REALLY low enough to trigger the LOCO, and the start/stall issue is gas flow related.

OT - RV Onan Generator

johndeere720GA

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bo

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johndeere720GA

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Roger in Iowa

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1970-1655

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jm.

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johndeere720GA

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johndeere720GA

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Billy Shafer

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wilson ind

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Bob

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