The Ford Barn

ckulchar · 04-20-2014, 05:44 AM

Had a regular Zenith carb on my late 1931 pu. Purchased a carb kit with the correct sized jets. Rebuilt carb then worked properly gav open 1/4 turn when warm.

Recently bought a used side bowl carb. Disassembled and cleaned the passages with the paper clip method. Reassembled and installed the carb. To my surprise it idles properly even after a hard test stop, doesn't leak. I open the gav valve one turn when cold. After the car warms up with the gav open 1/4 turn the truck doesn't pull like it should. I have to open the gav valve one turn then all is well.

What should I check next? Should I switch the main jet from the other carb?

Thanks in advance.
Charley

johnbuckley · 04-20-2014, 05:52 AM

yes, good idea to swap jets and see... sounds like main or compensator jet too small, or maybe partial blockage in those circuits.

Mitch//pa · 04-20-2014, 05:55 AM

another idea along with the jets is to check for any play in the throttle shaft causing it to suck air and run the carb lean. very common ..

Purdy Swoft · 04-20-2014, 11:25 AM

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I would rev it up and hand choke it untill it almost quits running a few times first. This will usually pull any blockage out of the jets. This is easier than removing and maybe upsetting the connection at the main jet.

04-20-2014, 05:44 AM	#1
ckulchar Senior Member Join Date: May 2012 Location: Amherst Ohio Posts: 157	another zenith carb question Had a regular Zenith carb on my late 1931 pu. Purchased a carb kit with the correct sized jets. Rebuilt carb then worked properly gav open 1/4 turn when warm. Recently bought a used side bowl carb. Disassembled and cleaned the passages with the paper clip method. Reassembled and installed the carb. To my surprise it idles properly even after a hard test stop, doesn't leak. I open the gav valve one turn when cold. After the car warms up with the gav open 1/4 turn the truck doesn't pull like it should. I have to open the gav valve one turn then all is well. What should I check next? Should I switch the main jet from the other carb? Thanks in advance. Charley

04-20-2014, 05:52 AM	#2
johnbuckley Senior Member Join Date: Jul 2010 Location: United Kingdom Posts: 1,443	Re: another zenith carb question yes, good idea to swap jets and see... sounds like main or compensator jet too small, or maybe partial blockage in those circuits.

04-20-2014, 05:55 AM	#3
Mitch//pa BANNED Join Date: May 2010 Location: Bucks County, PA Posts: 11,454	Re: another zenith carb question another idea along with the jets is to check for any play in the throttle shaft causing it to suck air and run the carb lean. very common ..

04-20-2014, 11:25 AM	#4
Purdy Swoft Senior Member Join Date: May 2010 Location: Alabama Posts: 8,099	Re: another zenith carb question Sponsored Links (Register now to hide all advertisements) I would rev it up and hand choke it untill it almost quits running a few times first. This will usually pull any blockage out of the jets. This is easier than removing and maybe upsetting the connection at the main jet.