Farmall B Zenith Carb Adjustment

calcubman · Dec 30, 2014

i just completed the restoration on my 1940 B
Farmall, and i have a carb issue, it starts up
right away but when it is running at any speed ,
i have to have the choke on about 1/4 way i have
taken the carb off and cleaned it as good as iti
can get, blew out with compressed air and
everything and it still has the issue, i have
tried adjusting the screw on top of the carb but
it does not do anything at any position ???????

Dean Olson · Dec 30, 2014

That's a classic fuel starvation symptom.

Back track to the fuel tank, sediment bowl,filter, filter in carb inlet, gas cap vent, run a small wire through all the ports in carb. I use torch tip cleaning tool with multiple wire sizes.

I've read on these forums about leaking manifolds, gasket or cracked. That creates a low vacuum issue. I've never had that happen. It's usually some tiny piece of debri I missed in the fuel delivery system.

It's frustrating, having been there and done that more than once. In my case I start over and check everything, again, till I find what I missed.

gene bender · Dec 30, 2014

Does the gasket between the two halves fit good and is the joint between the carb and manifold clead and a new gasket. You are sucking air someplace causing it to run too lean. If the fuel line was plugged pulling the choke would not help

calcubman · Dec 30, 2014

there is a new gasket between the carb and manifold, i will check.

old · Dec 30, 2014

If I remember right those carbs do not have an adjustable main jet and your is most likely still clogged up. The screw your adjusting is the idle jet so yes it will do nothing above an idle.
When you clean a carb you need to use a small wire to poke out the passage ways my self I use a torch tip cleaner tool to do that. You also need to use spray carb cleaner and air to make sure every passageway is clear of dirt and rust. You may get by by removing the plug over the main jet and then poking it out with a small wire. Have the gas turned on when you do that so any dirt.rust you loosen up will be washed out and to the ground

calcubman · Dec 30, 2014

thanks will try that
also.

Dblair · Dec 30, 2014

if the tractor is new to you it may not be the correct one as a Marvel-Schebler, I think, was original and the Zenith may not be the correct one.

Farmall B Zenith Carb Adjustment

calcubman

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Dean Olson

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gene bender

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calcubman

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old

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calcubman

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Dblair

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