John Deere B carb question

Beatles65 · Apr 11, 2010

I got the 1945 john Deere B carb all cleaned up and passages cleared and got the tractor running. That thing was so clogged up with rust!!!
On the carb there are two posts with circular discs that are used for the choke and the throttle. On my carb the disc and post for the throttle are giving me trouble. It likes to move and it causes my tractor to rev up and then die down. Does it need a new throttle shaft to make it stop moving??? Thanks for the help From Nebraska Andrew.

Greenday · Apr 12, 2010

Yes,you Need a new throttle shaft and bushings.

34gpa · Apr 12, 2010

You still have a idle circuit that isnt cleaned out and a new throttle flap never hurts either. Send me an email and maybe I can help. I just live south of Lincoln.

The Dukester · Apr 12, 2010

Mebbe it's carburetor trouble, the shaft probably is worn, but it could be you don't have the linkage adjusted just right. The throttle link rod running from the govenor should be adjusted to be half a hole long with the throttle lever at idle position (back but not all the way) to insure the throttle idle stop screw is meeting firmly against the vertical spring cushion stop on the carburetor. Then when the throttle lever is in the fully closed (all the way back position) the quadrant stop plate on the carburetor throttle shaft should rest solidly against the vertical stop post and the engine should die because the throttle disk should be seated closed in the carburetor venturi throat cutting off all the air/fuel mixture flow to the engine. The throttle linkage was designed this way to provide a method of stopping the engine because on these tractors there was no switch of any sort provided to cut off the ignition from the magneto.

IOWA NORTHEAST · Apr 12, 2010

Give her a squirt of either around the shaft, it has to be sealed so it doesn't suck air at random. Also that disk should be perfectly round.

Check that cotter pin on top, it has to have a washer on it to keep it from binding. Test it by holding the linkage in one spot--it should stop hunting.

IOWA NORTHEAST · Apr 12, 2010

Just had another thought, alot of NEW throttle bushings have to be reamed so they don't bind up (when and if you replace yours)

And like said before, it could be a plugged passage. That bottom one called the secret passage often is not cleaned. It will feel just like solid steel to a drill bit sometimes.

John Deere B carb question

Beatles65

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Greenday

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34gpa

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The Dukester

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IOWA NORTHEAST

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IOWA NORTHEAST

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