Super A carb problems

[cje3]

I'm being challenged by a carb problem that seems to have no end in sight. The tractor came to me third or fourth hand so I can only assume it's had many hands making repairs or changes. It currently has a zenith carb but there isn't a tag telling me a model number. I'm to the point of buying a new OEM carburetor but there seem to be so many that say they will work on a Super A and dropping $200+ on one that may or may not be correct isn't going to happen. Any suggestions on where I should look and what is in fact the correct part? Also it appears that the governor bump spring has been adjusted ( lock ring is loose) Is there a process to get this adjusted correctly? Thanks

 

[wore out]

I'm being challenged by a carb problem that seems to have no end in sight. The tractor came to me third or fourth hand so I can only assume it's had many hands making repairs or changes. It currently has a zenith carb but there isn't a tag telling me a model number. I'm to the point of buying a new OEM carburetor but there seem to be so many that say they will work on a Super A and dropping $200+ on one that may or may not be correct isn't going to happen. Any suggestions on where I should look and what is in fact the correct part? Also it appears that the governor bump spring has been adjusted ( lock ring is loose) Is there a process to get this adjusted correctly? Thanks

Two questions, what are the issues you are having with you carburetor, and where can you get a "new OEM carburetor" for $200?

As to the "bump spring", turn the adjusting screw CW/inward the very minimum amount that will stop low-speed "surging".

In my experience, if the carburetor is working well and the governor is in good shape the surge spring isn't even needed, many most other machines of the era didn't even have one.

 

[RTR]

I can help if needed. I actually have rebuilt oem carbs ready and might can help you understand what you need to do. Reach out if needed. [email protected]

 

[Gary Mitchell]

I'm being challenged by a carb problem that seems to have no end in sight. The tractor came to me third or fourth hand so I can only assume it's had many hands making repairs or changes. It currently has a zenith carb but there isn't a tag telling me a model number. I'm to the point of buying a new OEM carburetor but there seem to be so many that say they will work on a Super A and dropping $200+ on one that may or may not be correct isn't going to happen. Any suggestions on where I should look and what is in fact the correct part? Also it appears that the governor bump spring has been adjusted ( lock ring is loose) Is there a process to get this adjusted correctly? Thanks

I've restored 3 or 4 little binders and I always scrounged up a Marvel carb that would fit the application rather than mess with the Zenith. Salvage yards that have the old stuff have a lot of small MS carbs. I never found small Zeniths to be to my liking. The Marvels are super simple to clean out and use. gm

 

[Charlie M]

A note if you play with the bump spring - I've got 4 tractors with that governor and all of them either had a broken spring or one stuck in old grease. If yours is broke you can get new ones.

 

[DaveBN]

You need to tell us what problem your having. Carburetor may not be your only problem. Plugged air cleaner parts, leaking manifold, poor spark, bad governor, incorrect timing and bad spark plugs are often culprits acting like a bad carburetor.
Dave

 

[Geo-TH,In]

I'm being challenged by a carb problem that seems to have no end in sight. The tractor came to me third or fourth hand so I can only assume it's had many hands making repairs or changes. It currently has a zenith carb but there isn't a tag telling me a model number. I'm to the point of buying a new OEM carburetor but there seem to be so many that say they will work on a Super A and dropping $200+ on one that may or may not be correct isn't going to happen. Any suggestions on where I should look and what is in fact the correct part? Also it appears that the governor bump spring has been adjusted ( lock ring is loose) Is there a process to get this adjusted correctly? Thanks

I bought an aftermarket carb off amazon for my Farmall c. Works just fine. A perfect match. Free shipping and free return with prime. It was under $40.
If I recall all the small Farmalls use the same carb.

 

[cje3]

You need to tell us what problem your having. Carburetor may not be your only problem. Plugged air cleaner parts, leaking manifold, poor spark, bad governor, incorrect timing and bad spark plugs are often culprits acting like a bad carburetor.
Dave

Thanks to all who offered their thoughts. The tractor will start and run if I continue to fool with the choke but eventually it seems like it runs out of gas. (Tank is full) When its running I've sprayed carburetor cleaner around the intake manifold to see if there might be a leak but it made no difference. The spark is strong. I'm unsure of the governor. Cleaned the air filter and refilled the oil in it.

 

[cje3]

I can help if needed. I actually have rebuilt oem carbs ready and might can help you understand what you need to do. Reach out if needed. [email protected]

Thanks Will do

 

[crsutton81]

I'm being challenged by a carb problem that seems to have no end in sight. The tractor came to me third or fourth hand so I can only assume it's had many hands making repairs or changes. It currently has a zenith carb but there isn't a tag telling me a model number. I'm to the point of buying a new OEM carburetor but there seem to be so many that say they will work on a Super A and dropping $200+ on one that may or may not be correct isn't going to happen. Any suggestions on where I should look and what is in fact the correct part? Also it appears that the governor bump spring has been adjusted ( lock ring is loose) Is there a process to get this adjusted correctly? Thanks

The Zenith carb you have should be a 14007 model for the Super A's through 140's. Here are a couple things to check.

#1...in the upper portion of the sediment bowl under the gas tank, there is most times a fine screen. Ensure that it is clean. I have had some that no matter how clean things are, they would act up with them being left installed. If you gas tank is clean anyway, it can be eliminated.

#2....where the fuel line screws onto the carburetor, the elbow that should be there is actually a filter. Withdraw it from the carb and ensure it's clean. These tractors need a good strong gas flow or they'll hesitate. Hope this helps.

 

[Blackhole49]

Thanks to all who offered their thoughts. The tractor will start and run if I continue to fool with the choke but eventually it seems like it runs out of gas. (Tank is full) When its running I've sprayed carburetor cleaner around the intake manifold to see if there might be a leak but it made no difference. The spark is strong. I'm unsure of the governor. Cleaned the air filter and refilled the oil in it.

Using a clean container, does a good steady stream continue to run out of the float bowl with the drain plug removed, or does it peter out?

 

[cje3]

Using a clean container, does a good steady stream continue to run out of the float bowl with the drain plug removed, or does it peter out?

Actually as an after thought I did open the drain and there was a steady unabated flow. But thanks for the suggestion

 

[cje3]

The Zenith carb you have should be a 14007 model for the Super A's through 140's. Here are a couple things to check.

#1...in the upper portion of the sediment bowl under the gas tank, there is most times a fine screen. Ensure that it is clean. I have had some that no matter how clean things are, they would act up with them being left installed. If you gas tank is clean anyway, it can be eliminated.

#2....where the fuel line screws onto the carburetor, the elbow that should be there is actually a filter. Withdraw it from the carb and ensure it's clean. These tractors need a good strong gas flow or they'll hesitate. Hope this helps.

Thanks for the tip Jim

 

[560Dennis]

i think more info is needed , that zenith is a robust carburetor that has function well on these tractors for 75 years.
i have not seen one that can’t be corrected to run a tractor as design .
Something else is the cause , just guessing what yours is doing with the governor bumper , that linkage adjustment,
Im saying you going to spend money on new carburetor for your tractor ,and install it and the tractor will run worse.
Look up in the resources hear on YT up in the header and read the how tos and get a game plan to measure what our engine is doing now before you change anything.
make a complete outline don’t overlook any and guess
outline completely check it all .
Fuel flow ,
Vacuum .
compression
timing
viz
get back to us .

 

[cje3]

i think more info is needed , that zenith is a robust carburetor that has function well on these tractors for 75 years.
i have not seen one that can’t be corrected to run a tractor as design .
Something else is the cause , just guessing what yours is doing with the governor bumper , that linkage adjustment,
Im saying you going to spend money on new carburetor for your tractor ,and install it and the tractor will run worse.
Look up in the resources hear on YT up in the header and read the how tos and get a game plan to measure what our engine is doing now before you change anything.
make a complete outline don’t overlook any and guess
outline completely check it all .
Fuel flow ,
Vacuum .
compression
timing
viz
get back to us .

Thanks for the suggestions Dennis. The head was redone with new valves, guides and seals, magna fluxed and reinstalled. Compression is within specs as well as timing. When I disconnect the fuel line from the carb it flows freely, but how/what should I do to check vacuum? As an aside this site/forum has been a wellspring of knowledge. Thanks to all for your help.

 

[used red MN]

#2....where the fuel line screws onto the carburetor, the elbow that should be there is actually a filter. Withdraw it from the carb and ensure it's clean.

Just to reiterate, he is referring to is number 25 in the link to the manufacturer’s carburetor parts diagram. CNHI Farmall Super A parts catalog
Pull it out and check its cleanliness. If it is plugged and only allows a dribble to pass by it as it sets with the engine not running it will slowly fill the carb bowl. To test for flow “into” the carb you have to pull the drain plug and wait 5 seconds or so for the carb bowl to drain. Once empty that is when you find out what the actual flow is coming through the float needle into the carb. Just FYI that link will allow you to view all the parts diagrams for that tractor. Just click the Farmall Super A tractor at the upper left and select the desired section to view.

 

[560Dennis]

Thanks for the suggestions Dennis. The head was redone with new valves, guides and seals, magna fluxed and reinstalled. Compression is within specs as well as timing. When I disconnect the fuel line from the carb it flows freely, but how/what should I do to check vacuum? As an aside this site/forum has been a wellspring of knowledge. Thanks to all for your help.

I use this method , best I done with my C s is about 21 . Use 1/8 hose barb into the tune up port ( in photo) in the intake. I warm up engine ,record idle vacuum low idle at475 to 525 rpm then at high idle 1815 to 1850 super c Farmall A sa I’d about 1550 rpm ,record the vacuum number. Need to record numbers to verify that you’re making improvements .
when you have numbers you will check after you do anything like card idle screw in photo adjust, timing adjust viz
So if the needle is steady like in photo, experiment to achieve highest vacuum .
If the needle fluctuate quick and wildly on the gage , get ,a trouble shoot chart off the image on Google or get with me and I can point u to corrective actions .
Question
Did you remove the screen filter in the input fitting and clean it ? . I remove the plug on bottom of carburetor for another fuel flow test. fuel coming from line tells you it flows, but not into the fuel to Venturi For atomizer.
This a brief example, Your engine will test out different, and the gage will point the way to improve performance.
ask for more details