Zenith carb issue

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Mcald62
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Zip Code: 06468
Tractors Owned: 1955 Farmall Cub
1975 Cub Lo-boy 185
1947 Huber Maintainer
1962 Schramm 125 Pneumatractor
Circle of Safety: Y

Zenith carb issue

Postby Mcald62 » Thu Nov 23, 2023 3:34 pm

I recently bought a 1975 Lo Boy 185. It runs great with the choke completely closed and stalls when I open it fully. I’ve gone through the carb twice now and cleaned everything thoroughly. I’ve rebuilt a number of Zeniths and never had a problem. The fuel tank is like new and the sediment bowl and fuel line are spotless. The only thing I have not done is check the float level clearance. I also have not replaced either the intake or bowl gaskets as they appear to be intact. Any ideas as to why it wont run properly ? Should I buy a rebuild kit and go through it again?

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Don McCombs
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Re: Zenith carb issue

Postby Don McCombs » Thu Nov 23, 2023 3:36 pm

Have you checked the filter screen in the carburetor fuel intake? It’s part of the brass fitting.
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Mcald62
Posts: 13
Joined: Fri Jul 09, 2021 7:48 am
Zip Code: 06468
Tractors Owned: 1955 Farmall Cub
1975 Cub Lo-boy 185
1947 Huber Maintainer
1962 Schramm 125 Pneumatractor
Circle of Safety: Y

Re: Zenith carb issue

Postby Mcald62 » Thu Nov 23, 2023 5:03 pm

Yes. It’s like new.

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ricky racer
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Re: Zenith carb issue

Postby ricky racer » Thu Nov 23, 2023 6:34 pm

What you're describing is a blockage in a carburetor jet or passage. You'll need to disassemble the carb again and determine where the blockage or partial blockage is.
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Mcald62
Posts: 13
Joined: Fri Jul 09, 2021 7:48 am
Zip Code: 06468
Tractors Owned: 1955 Farmall Cub
1975 Cub Lo-boy 185
1947 Huber Maintainer
1962 Schramm 125 Pneumatractor
Circle of Safety: Y

Re: Zenith carb issue

Postby Mcald62 » Thu Nov 23, 2023 7:20 pm

I guess if I have to take it apart for a third time I will buy a rebuild kit.

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Re: Zenith carb issue

Postby tst » Thu Nov 23, 2023 9:04 pm

did you pull the main jet out on the bottom of the bowl, make sure passages in body are clean ?

Mcald62
Posts: 13
Joined: Fri Jul 09, 2021 7:48 am
Zip Code: 06468
Tractors Owned: 1955 Farmall Cub
1975 Cub Lo-boy 185
1947 Huber Maintainer
1962 Schramm 125 Pneumatractor
Circle of Safety: Y

Re: Zenith carb issue

Postby Mcald62 » Thu Nov 23, 2023 9:27 pm

Yes I did clean the main jet

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Dale Finch
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Re: Zenith carb issue

Postby Dale Finch » Thu Nov 23, 2023 9:54 pm

Do you have an online filter installed? If yes, is it for gravity flow (no fuel pump)? Is it installed the correct direction?
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Don McCombs
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Tractors Owned: "1950 Something" Farmall Cub
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1948 Farmall Super A
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Location: MD, Deep Creek Lake

Re: Zenith carb issue

Postby Don McCombs » Thu Nov 23, 2023 10:51 pm

For Zenith parts and kits, contact McDonald Carb & Ignition.
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MD, Deep Creek Lake

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Re: Zenith carb issue

Postby staninlowerAL » Fri Nov 24, 2023 4:20 am

Visually Check the choke butterfly to see if it is in the position that you think it is. Maybe it is operating backwards i.e. you think it's open and it is actually closed. JMHO Stan
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Mcald62
Posts: 13
Joined: Fri Jul 09, 2021 7:48 am
Zip Code: 06468
Tractors Owned: 1955 Farmall Cub
1975 Cub Lo-boy 185
1947 Huber Maintainer
1962 Schramm 125 Pneumatractor
Circle of Safety: Y

Re: Zenith carb issue

Postby Mcald62 » Fri Nov 24, 2023 8:03 am

No filter and the choke is operating properly.

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Re: Zenith carb issue

Postby Gary Dotson » Fri Nov 24, 2023 8:25 am

It sounds like you still have a blockage somewhere in the main metering circuit. I agree with Don, contact Morgan at McDonald Carb and Ignition. Not only will he have the parts you need, he’s very knowledgeable on Zenith carbs.

Mcald62
Posts: 13
Joined: Fri Jul 09, 2021 7:48 am
Zip Code: 06468
Tractors Owned: 1955 Farmall Cub
1975 Cub Lo-boy 185
1947 Huber Maintainer
1962 Schramm 125 Pneumatractor
Circle of Safety: Y

Re: Zenith carb issue

Postby Mcald62 » Fri Nov 24, 2023 8:48 am

Thanks, I will do that.

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SONNY
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Re: Zenith carb issue

Postby SONNY » Wed Dec 06, 2023 11:11 am

internal passages blocked and no way to clean them. had some here the same way. IF anybody knows how,---speak up!!! Only have 2 cubs left here now and the main one messed up so I put a chimineese knockoff on it 2 years ago and still runnin. was plowing with it til the ground got muddy! The other one has sat for 6 years with the grader blade under it and I lost interest in it.


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