Carburetor Adjustment

Thu May 16, 2013 7:26 am

I need some help with the zenith carburetor adjustments.
When I got the tractor it would miss at an idle, but run great in the midrange & at wide open throttle. I turned in the air adjustment (top of the carb) in to richen it up. That solved the miss at an idle, but now the midrange is not well. It cuts out while accelerating to full throttle. If I turn it back out 1/4 turn, then it goes back to missing at an idle, but the midrange is ok again.

I can't seem to find a place where both run well. Is there a better way to adjust the carb than by tweaking and running it?

Re: Carburetor Adjustment

Thu May 16, 2013 7:34 am

Try carburetor cleaner in the fuel. Then operate the tractor for a while before making the carburetor adjustments.

Re: Carburetor Adjustment

Fri May 17, 2013 7:01 am

I need help adjusting the carb, not cleaning or rebuilding it.
I finished up the winter tank with 1/2 can of seafoam in it. Filled with fresh gas (no ethanol) last week.

Does someone have a procedure on how to properly adjust the carb?
Are any special tools recommended to help adjust the air to fuel mixture?

Re: Carburetor Adjustment

Sat May 18, 2013 10:04 pm

If my previous, inexpensive, suggestion doesn't work, you will need to completely clean the carburetor. You should also check the ignition system/ignition timing.

Tweeking, your cited adjustment method, is correct for the Zenith carburetors standard on Cubs.

Re: Carburetor Adjustment

Mon May 20, 2013 5:52 am

I agree with eugene. You may have a leaky float so be sure to check that.

Re: Carburetor Adjustment

Mon May 20, 2013 6:09 am

The description sounds like you may have a vacuum leak, you might check that.