carburetor

Lester Warner · Nov 26, 2010

My John Deere D will only run when the choke is on half way .It will quit when the choke is open all the way. It is a Marvel,and has just been rebuilt. It has two adjustments, idle needle,and load needle.I have tried every position,and no luck. Les

optiman · Nov 26, 2010

clean it

Jerry/MT · Nov 26, 2010

Check the spark first. Weak sparks need a richer mixture. If the spark is OK(FAT AND BLUISH-WHITE, the color of lightning, then look for an air leak around the metering section of the carb. The throttle shaft seals, the gasket between the intake manifold and the carb, manifold gasket at the head and cracked or rusted out intake manifold are the usual culprits.

Walt Davies · Nov 27, 2010

Check the line from the tank to the carb for obstructions.
Walt

John B. · Nov 27, 2010

Sounds like you may have a vacum leak some where. With it running spray some WD40 where the carb and manifold bolt together then where the manifold and head bolt together. If the engine rpm changes you have a leak. I don't recommend starting fluid for doing this, it works but any spark created from any where on the engine and you'll have a fire. Let us know what you find.

Lester Warner · Nov 27, 2010

Thanks for the advice,this gives me a lot to check out. I am bringing this 1944 D out of a long sleep.It has a new rebuilt Wico mag,new plugs, and wireing, total rebuilt carb by a tractor shop. It is hand start. Les

Oldmax · Nov 27, 2010

Most of the time when that happens the main jet partly stopped up.

PopinJohn · Nov 27, 2010

Using the choke to keep the engine running causes the carburetor to supply fuel to the air stream through the main nozzle.
Obviously a rich mixture is required when starting a cold engine, especially in cold weather.
However, if the choke continues to be needed, it is because enough fuel/air cannot be supplied through the idle circuit passages and orifices.
When the entire idle circuit is 100% clean and adjusted, the engine will run at low and high RPM with the load needle closed and the choke off.
Won't accelerate or pull the hat off your head, but will run.
Sounds like your carb wasn't cleaned properly, or became contaminated afterward.
If we can help our contact information is www/popinjohn.com

Anonymous-0 · Nov 27, 2010

I would have to agree with a couple of the others... clean the carb!! I had a red tractor that would only run with the choke partially on... when I painstakingly rebuilt the carb, I found a couple of "micro passages" that had been plugged for quite some time. After soaking/scrubbing/& picking with a fine wire (careful not to break it off in the passage!) off & on for a couple days, finally got everything cleaned & reassembled... runs like a champ now!!! ...D

Lester Warner · Nov 27, 2010

When the carb wss rebuilt,and spent time in the tank, I assumed that nothing more was to be done,but maybe blockage accured after I installed it. It also back fires once in a while when starting. Ear protectors are a must,believe me. I replaced the Edison splitdorf mag with a re built Wico,would the timing be the same according to the manuel? Les

carburetor

Lester Warner

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optiman

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Jerry/MT

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Walt Davies

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John B.

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Lester Warner

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Oldmax

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PopinJohn

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Anonymous-0

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Lester Warner

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