Friday, December 3, 2021


Keep your generator linkage clean to prevent stoppages

By Greg Illes
Onan generators, typically 4000W (3600W for propane), are often a feature on mid- to large-size RVs. You can recognize these ubiquitous products by the presence of a large green box in place of a storage compartment.

While generally quite reliable, these units have a failure mode that is deceptively complex, yielding an error code that essentially says, “Take me to your Onan service shop.” If you own or operate an Onan, there’s an easy maintenance action you can take to prevent failures and expensive shop visits.

Inside the generator cover (two hand levers to open) you will see the engine and its carburetor at the upper right. On top of the carburetor is control linkage that governs the speed of the engine under different load conditions. If this linkage gets dirty, dusty or corroded, it can start to bind up. Since it’s operated basically by air pressure from the cooling fan, it doesn’t take much to get it “sticky.”

This happened on my RV after several miles of dusty roads. I heard the generator “rev up” a little bit one day after the microwave shut off, and then the generator shut down and delivered an error code 14 — “Overfrequency Fault.” Normally, such a fault is due to electronic failure in the generator electronics. But in this case (and several times since), the issue was simply that the feedback linkage could not respond quickly due to dirt accumulation, and the motor over-revved.

Blowing out the accumulated dust and putting a small drop of Tri-Flow on the pivot points was all that it took to get my volts and watts flowing smoothly again. Now I do this proactively whenever I’ve been in dusty conditions, or if it’s just been a long time since I cleaned up.

A compressed air source helps a lot, but if you’re out on the road and don’t have such access you can get the linkage free just by wiggling it full-stop by hand (of course, don’t do any of this with the generator running). If you see evidence of crusty corrosion, use a TINY bit of lubrication — just a drop of WD-40 or light oil will do. Too much lube will only hasten the accumulation of more dirt.

Greg Illes is a retired systems engineer who loves thinking up RV upgrades and modifications. When he’s not working on his motorhome, he’s traveling in it. You can follow his blog at



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1 year ago

Thanks Greg for the great tip and illustration!

1 year ago

Hi Gregg: I have a problem with my 1994 Onan Genset 7kw. I changed the rubber fuel line from the steel line from the tank to the genset fuel pump – now it won’t start! It ran perfectly prior. I’ve checked the oil, fuses and all visible things. I tried gently blowing in the rubber line after adding fuel to it. I tried blowing air across the top end of the line by the carburetor to create a slight vacuum (suction) – no fuel flow! I’ve contacted Onan to no avail. I also contacted the Rv Doctor – Gary Bunzer. He suggested an air lock etc. It is a Mod: 7NHMFA261060. SN: B943122211. TTime: about 290 hours. 6.8 kw.

Any suggestions you may have would be greatly appreciated. Thank You.

1 year ago

Hey Greg. Nice article, wrong model for me. I have an Onan 6000 and am not aware of how to retrieve error codes; though I would like to. My unit runs about 20 minutes and then just shuts down. I know of over-temperature and low oil sensors and have addressed both ventilation and oil level to be sure they are ok. An error code would sure be nice.

Last edited 1 year ago by Hook-n-Haul
Michael Daus
1 year ago

Great info Greg! My propane Honda does this. Wonder if it’s a similar condition? Been trying to figure it out. The Honda EU2200i was converted to propane and sold by GenConnex.

Abe Loughin
1 year ago

Good advice Greg, but may I suggest using CRC Powerlube with PTFE as the lubricant of choice? The Powerlube dries, leaving a film of PTFE (teflon). This way you get continued lubrication and it doesn’t attract and hold dirt. Also I might add, exercise your generator monthly by running it with at least a 50% load and using a fuel stabilizer when in storage.

1 year ago

Again I say “Onan, old Indian word for big, green boat anchor”. I’ve had three of them, hopefully there will not be fourth.l

1 year ago

Small cans of compressed air are easy to find and easy to carry along with your other ‘stuff.’
Try a sewing shop, if nowhere else.
A very good tip, by the way.

1 year ago
Reply to  Tom

Computer dept usually would have canned air