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Super A carb not opening up

Farmall Super A, AV, 100, 130, & 140 1939 - 1973
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CDKL
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Super A carb not opening up

Postby CDKL » Thu Jun 09, 2022 5:49 pm

Hello all, I’m having some issues with a carb on a 1950 SA. I took it apart, cleaned it really well, tested the float etc. got it all back together. And it will crank just fine, I can take the throttle rod off and try to manually open it up and it just won’t do it (will not with the rod attached either). Would spark plugs have anything to do with this or not, or is it just a carb issue? I’m just trying to make sense of it all. I will post a small video link, as to what it doing. I would appreciate any help you guys could throw my way.

https://youtu.be/qcVty3Y6fiw

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Rick Spivey
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Re: Super A carb not opening up

Postby Rick Spivey » Thu Jun 09, 2022 6:58 pm

It acts as if there is something wrong or loose concerning the butterfly connection to the shaft, or the shaft connection to the throttle rod connector. See if there is some play or looseness in that part of the system.
Rick Spivey
'52 Cub ("Great Personality") 148xxx
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CDKL
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Re: Super A carb not opening up

Postby CDKL » Thu Jun 09, 2022 7:24 pm

Yes it does seem very loose to the fact that after i disconnected the rod from the carb, I was concerned that was going to have to hold the butterfly up so that is was open enough inside the carb to crank. However shouldn't it open up and rev a lot higher when I open the throttle? It seems that there is something weird going on inside the carb that's not allowing that to happen. When I remove the carb and the top half is exposed you can manually work the butterfly back and forth and see the throttle valve plate open and close as it should. It has me puzzled, however I am a newb at this whole thing.

Jim Becker
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Re: Super A carb not opening up

Postby Jim Becker » Thu Jun 09, 2022 10:02 pm

It should absolutely roar (and blow up) with the throttle flipped open. Could the timing be way off?

CDKL
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Re: Super A carb not opening up

Postby CDKL » Fri Jun 10, 2022 5:30 am

Jim, I have no idea. How would I be able to check the timing? It wouldn’t crank the other day at all, and I pulled one of the plugs out and it was pretty nasty. Cleaned it up along with one more, (the other two were a different size, they will be coming out today) and she crank right up, but now I’m this point. I’m at a loss

Jim Becker
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Re: Super A carb not opening up

Postby Jim Becker » Fri Jun 10, 2022 2:37 pm

I think at this point, you should fix anything that is a known problem before continuing to diagnose others. At this point, I think it means putting in 4 new matching spark plugs. I suggest something heat-equivalent to a Champion D-21, in whatever your favorite brand is. It may also mean to do a complete tune-up.

It seems like we are doing a lot of one-step-forward that turns into two-steps-back. Getting this tractor running properly may take a long time. You may make a lot more progress if you find somebody local that come in person and work with you to get through these issues.


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