Farmall Super A

[Mississippiruss]

I have a Farmall Super A that runs great but will not carry a load, it tends to cough so to speak when the plows are down! Any help would be appreciated

 

[Janicholson]

I have a Farmall Super A that runs great but will not carry a load, it tends to cough so to speak when the plows are down! Any help would be appreciated

When a tractor is under load the governor opens the carb much wider than when just a full throttle no load condition (high idle). This uses fuel 4 or 5 times faster than high idle and demands a full flow from the tank. A full flow to the carb can be checked by using a open container (like a clean gallon can) under the carb and removing the (square headed) drain plug from the bottom. This will flow very fast at first, then slow a little as the float bowl empties and fuel flows as fact as it can through the needle and seat. That flow should be a pint every 60 seconds to a minute and a half. If the flow slows to dribbles or less there is restriction in the supply. the tank outlet, the screen in the sediment bowl, and the screen in the fitting where the line attaches to the carb are all places to look. A good LED light for looking into the fuel tank for trash can also be of help. Don't use a clear plastic fuel filter, they are too restrictive. If you feel the need far a filter, NAPA sells filters for gravity systems that do work. Jim

 

[used red MN]

Hello MS, welcome to YT! To add to what Jim has said does it immediately run bad when the load is applied, misfiring if you know what that might sound like? That is likely spark plugs or points. If the running bad starts after a delay of approximately 20 seconds to a minute then your most likely culprit is fuel delivery as Jim has covered. This is for the reason that ties in with Jim’s explanation. If you have a flow restriction under a light load the carburetor bowl will stay at the proper level. When you add the heavy load the restricted flow will not keep up with the amount the jet is sending into the air stream. Eventually the level of fuel in the carb drops to a point the air fuel mix starts to lean out. This is when the engine “coughs” as you call it. The time for this to happen would be the time it would run well then go into struggle mode.
For this tractor in my opinion the flow rate will be okay out of the carb if it is in the 1 pint every 3 minutes range. That is 2.5 gallons per hour(gph) still above the amount your tractor uses under full load which is 1.6 gph. Getting down to this precise of measurement you have to delay the catch time about 5-8 seconds after the plug is pulled so the reserve in the carb bowl does not influence the flow rate.
Humm, that got longer than I expected.

 

[grandpa Love]

I have a Farmall Super A that runs great but will not carry a load, it tends to cough so to speak when the plows are down! Any help would be appreciated

You ain't dealing with a lot of horse power to begin with so every little thing kills a couple of those horses. Fuel flow has been covered. Couple things we do. 1- inspect and adjust the linkage from throttle lever all the way to the carb. 2- inspect the governor, replace any weak or broken parts ( springs , bearing). 3- if it's a distributor check and adjust the timing. Which is simpler than it sounds, loosen the distributor ( in the middle, not where it bolts to the engine) with the tractor running twist it slowly back and forth, you should hear the "sweet spot"....... And please let us know what you find and what the fix is. This helps others

 

[casecollectorsc]

I have a Farmall Super A that runs great but will not carry a load, it tends to cough so to speak when the plows are down! Any help would be appreciated

Open the load needle on the carb. 1/2 turn and see if it helps.