Onan carb issue

Kotaboy · 07-30-2023, 01:58 AM

Looking for some help. Just purchased a 2019 Thor with an Onan 4KY-26100R thats flooding. It has about 30 hrs on it. I thought maybe bad gas, as it sat for a while. After trying about everything, I pulled the carb, and took the bowl off. It wasn't bad. Looking at the float and needle, it seemed to me like the float did not have enough travel to close. I also took the altitude cap off and tried adjusting completly closed and still flooding?? I'm lost. Looking for input. Thanks in advance.

ducksface · 07-30-2023, 02:06 AM

New Chinese onan carbs are $16 to $30 on Amazon.
All cheap Chinese carbs I've bought were flawless.
Try that instead.

**16ACE27** · 07-30-2023, 02:43 AM

Why do you think it's flooding? Do you see/smell gas when priming it?

DavidEM · 07-30-2023, 12:30 PM

If it really is flooding it is probably due to the float valve not closing maybe due to ethanol gunk, junk in the valve or bad assembly. All will be corrected with a new carb. Or soak yours overnight in carb cleaner. Then blow on the fuel inlet while pushing up the float and check that it seals.

David

Kotaboy · 07-30-2023, 12:31 PM

I don't see or smell gas outside of the carb. As soon as I crank to start it may fire quickly, then quit. Pull the sparkplug, and its soaked.

**16ACE27** · 07-30-2023, 02:24 PM

Quote:

Originally Posted by Kotaboy

I don't see or smell gas outside of the carb. As soon as I crank to start it may fire quickly, then quit. Pull the sparkplug, and its soaked.

Do you prime it per the starting instructions in the manual?

Kotaboy · 07-30-2023, 08:55 PM

Yes, initially tried everything per the manual. But now, with everything dry, just hit the start button and floods out the plug right away. I think the only remedy is new carb!

DavidEM · 07-30-2023, 09:57 PM

Disassemble the carb, soak it in carb cleaner overnight and turn the parts over at least once. Has worked for me every time for ethanol gunked parts.

Won’t help if there is something keeping the float from shutting off the gas valve as you indicated. Blow in the gas inlet and lift the float to see if it shuts off. If not there is a tab on the float that the float valve sits on that can be bent to make it work.

David

ducksface · 07-30-2023, 10:08 PM

Quote:

Originally Posted by DavidEM

Disassemble the carb, soak it in carb cleaner overnight and turn the parts over at least once. Has worked for me every time for ethanol gunked parts.

Won’t help if there is something keeping the float from shutting off the gas valve as you indicated. Blow in the gas inlet and lift the float to see if it shuts off. If not there is a tab on the float that the float valve sits on that can be bent to make it work.

David

This type of work pays you $10per hour IF it works.

https://www.amazon.com/Carburetor-Ge...a-834916079730

Buy the carb that comes with gaskets, two filters and a handy shut-off valve.

DavidEM · 07-31-2023, 02:38 AM

Quote:

Originally Posted by ducksface

This type of work pays you $10per hour IF it works.

https://www.amazon.com/Carburetor-Ge...a-834916079730

Buy the carb that comes with gaskets, two filters and a handy shut-off valve.

Agreed, but my personal labor rate is cheap. And there is something satisfying about fixing it rather than replacing the whole thing.

David

happy · 07-31-2023, 02:22 PM

Since suggestions and solutions have been proffered, please allow a question.

With an Onan 4,000 gas engine:
Do you long term Onan owners think that a 2x per season use of Seafoam in the moterhome fuel tank is enough to prevent ethanol gunk in the Onan carb? We have been using a little stronger solution than the label says before we drive on a long trip and try to use about 3/4 of that tank before stopping for fuel.

DavidEM · 07-31-2023, 04:00 PM

I use Stabil in the gas for 5 mo of winter storage and run the generator for 15-20 minutes with the AC load on to suck in the treated gas.

During camping season I don’t use Stabil but I do run the generator every other month as above to suck in fresh gas.

So far so good.

David

The Gritz Carlton · 07-31-2023, 08:55 PM

Quote:

Originally Posted by ducksface

New Chinese onan carbs are $16 to $30 on Amazon.
All cheap Chinese carbs I've bought were flawless.
Try that instead.

^^^This advice is the best and shortest point to resolution. I rebuilt Holley and Rochester carbs in the 60's and 70's. Carbs ain't what they used to be...especially with ethanol. Once they cough, you'll never get them right again. Just buy a new one and be done with it.

Beau388 · 07-31-2023, 10:47 PM

Quote:

Originally Posted by The Gritz Carlton

^^^This advice is the best and shortest point to resolution. I rebuilt Holley and Rochester carbs in the 60's and 70's. Carbs ain't what they used to be...especially with ethanol. Once they cough, you'll never get them right again. Just buy a new one and be done with it.

As a guy with two Corvairs with 4 individual carbs each, I am very familiar with rebuilding single barrel Rochester carbs. I carry a spare fuel pump, air filter, carburetor with gaskets and spark plug for my KY.

Kotaboy · 08-04-2023, 07:45 PM

I solved my issue with the flooding. I presume someone before myself pulled the bowl off to clean or ??? What I found out was that there was a gasket washer missing on the inside of the bowl at the bottom where the solenoid screws into the housing holding the bowl on. Running great for now. Thanks to all that tried to help.

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