Generator noise

[Jasonw730]

I have a 2013 Raptor Velocity and the Onan 4500 generator sounds awful. It has a new carb and fresh oil. I have a video of it and you can hear it but I don’t think I can attach a video. Sounds like it’s going to shut off but it doesn’t. Could it be spark plug?

[flybouy]

When diagnosing any gasoline engine for rough idle the spark plug would be the first thing I check. Pull it, smell it, check the gap or for the few bucks it costs just replace it. Next step, change the fuel filter, again just a couple bucks.

Check the fuel. Run some in a glass jar and let it set for a while. Check for sediment settling out or the presence of water. Ethenol fuel is know to "attract moisture" when it sets unused for long periods of time.

With a 9 year old engine it could be several different components that can be causing an issue. Did it ever run ok and this is recent issue? What diagnostics have you done (if any) before replacing the carb?

[Jasonw730]

I will start with the spark plug thank you.

[sourdough]

2013? What kind of fuel have you been using and what do you do with it when you store the RV? Modern day fuel plays havoc on those engines if just left in there.

[roadglide]

The awful surging Onan generator. I replaced the carburetor on my 5.5 onan and it surged . Mine has a spring and flat bar with holes by moving the spring lower or higher will adjust throttle speed . There is a lock bolt on the top of that apparatus for fine turning the engine rpm. It’s the governor when the engine is under load . Also manually push that lever see if the engine levels out.

[wiredgeorge]

Originally Posted by Jasonw730

I have a 2013 Raptor Velocity and the Onan 4500 generator sounds awful. It has a new carb and fresh oil. I have a video of it and you can hear it but I don’t think I can attach a video. Sounds like it’s going to shut off but it doesn’t. Could it be spark plug?

First thing Jason, make sure you add the personal info to your profile and then also add a signature with year, make and model of camper and tow vehicle. Makes answering your questions a lot easier.

As far as your generator with the new carburetor, is there a fuel filter? Was it changed? Next, is the fuel fresh? If it has been in the system for awhile, was there fuel stabilized added? If the fuel has been there awhile, how long? Cleaning the plug might not hurt but will likely not help. Is the new carburetor an OEM Onan or aftermarket?

[roadglide]

Originally Posted by sourdough

2013? What kind of fuel have you been using and what do you do with it when you store the RV? Modern day fuel plays havoc on those engines if just left in there.

I took care of my onan. The problem with My oem Carburetor it had a cracked float with 400 hours, Even Onan couldn’t replace the float because of damn Sam EPA emissions . I bought a $60 carburetor from Amazon it has been working flawlessly after setting the governor idle .

[jsb5717]

You've got some good troubleshooting ideas here. As a general rule I will use only ethynol-free gas with my small motors like mower, pressure washer, and generator. I have found that these small-engine carbs are fairly easy to tear down and clean as they do tend to get gunked up a bit. But the ethynol-free gas tends to keep them running cleaner and is helpful especially if they sit for long periods. Also, if I know it's going to sit for a while I will shut off the gas supply and run the carb dry before storing. Those simple things have helped me for several years.