Onan 5.5 - New Carb Time?

Question

Onan 5.5 HGJAB Spec D. ABout 400 hours on it. I screwed up and didn't exercise it. It ran, but real rough and smoke. Changed plugs and filters (gas and air). Plugs were dark and damp. Gets plenty of gas. Did the Sea Foam Spray in the carb several times and let it sit for hours and days. Now runs smoother (but not perfect. Still smokes.

From everything I've read, it is new carb time. I'd burn $60 in gas taking it to the Onan place and if they change the carb it seems to be in the $400 range. I can get an OEM one for $240. I hate to parts swap but I think I've narrowed the possibilities down to it being an acceptable risk. At least I'd have a spare carb if that wasn't the solution:)

Comments/Critiques?

ninerbikes · Answer

Is it possible to pull the carburertor off, tear it down, and clean out all the brass jets in the carb, by removing them, soaking them in carb cleaner and reinstalling them, to see if it now runs right?

Worth a try if you are long on time and short on money.

blackdiamond · Answer

Yes new carb time.......I took mine apart and cleaned the bowl and the jets....helped but was still not right, I bought a carb off amazon now it purrs.

gjac · Answer

Mine is 19 years old and I thought it was time for a new carb. After cleaning and doing the Seafoam through the carb, which helped I remove the intake line and put it in a gal can of gas and a can of Seafoam and ran it under load for 1 hr and that fixed the problem. Now every year or so I do this just for maintenance when I exercise the gen set. It is also a good way to find out what your genset uses per hr. I use 1/2  gal/hr with 2 AC running.

mfox20 · Answer

My previous older Class A with the Onan 5000 had the same issue. I removed the carb, disassembled and soaked all the parts in SeaFoam for 3 or 4 days. You can use some fine wire to help clean the jets. Blow everything out good and let it sit a couple more days in the SeaFoam. Mine ran great after that. The genny had not been run in 2 years when I purchased it.

Hope this helps.

belgique · Answer

Thanks all. Makes me feel better about going for the new carb. I know a lot of folks do it but there are many warnings out there to not rebuild/take apart the carb because of fire risk. Since the genset is right under my bed, I think I'll spring for the new carb. Again, thanks for the counsel.

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Onan 5.5 - New Carb Time?

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