Super C Erratic Misfire

I have a Farmall Super C from 1953 I believe and ran into a problem a few years ago when the tractor started erratically misfiring (sounds like its about to run out of gas) so it was parked for a few years when we recently bought a new zenith carb to solve the problem to no avail, still misfiring. It was also surging bad so I pulled the governor housing off and replaced a broken adjustment spring and the surging stopped but still misfired, cleaner the condenser points and put in new plugs but still surged, could it be ignition problems or compression problems? The tractor fires right up most of the time which leads me to believe its not compression, and a cant find any diagrams on adjustments for the zenith carb, I see the screw on top for the float height adjustment, but there is also a bolt right across from the fuel inlet fitting, is this for air or fuel of just to hold it together? Could there be an air leak somewhere I dont know about? Help would be much appreciated, thanks.
Logan

I also set the distributer points to the spec in the book

there is no screw to set float level ,.. that is done manually when carb is apart. and if you set the points post what you set then to. AND ALSO check the compression is always first . then you know you have compression and proceed to next step. have you check the cap for cracks? is the plug wires on correctly? check and post as it can be that simple. maybe the carb main needle needs o be turned out.

Check the distributor shaft for side to side play. Too much changes timing and point gap.

I have checked the cap and no cracks, and confirmed that all plug wires are in the correct order, I will run out and buy a compression tester whenever I have time, and I set the point gap to .020

I thought that could be a problem but there no side to side play in the shaft

Hello LSC welcome to YT! You say it acted like it was running out of gas but all you did was throw a new carburetor at it like a magic wand. The carb has to get gas at the proper amount into it to make the engine run. Does it seem to start up and run fine for a few minutes and then start acting up? If so this is a sign of not enough fuel getting into the carb. Old tractors that set for a while usually get crud and residue built up in the tank and fuel line. Pull the line off the carb and open the gas valve. You should have a flow out of it nearly like urinating. If it slows to a trickle then you have a problem. It could be in the sediment bowl below the tank which should have a fine screen in the top of the glass or up in the tank where the fuel enters it. Check that all out, look down from the top with a good flashlight and see if there is crud down in the bottom around the fuel outlet. Also you have a new carb, but check the fitting that the fuel line hooks to, pull it out it has a fine strainer screen that can plug especially if there was a lot of crud built up in the line. All set and done you should be able to pull out the carb drain plug on the bottom of the bowl and it should give you a continuous flow and NOT slow to a dribble.
Here is a video to watch this should help you out with some of the misinformation you are giving like the carb having an external float adjustment. I did not watch the video but I know what he puts out is quality information because I have watched some of his other videos. I think it is possible that the carb on your tractor only has an idle adjustment needle and a fixed high speed jet that does not have an adjustment needle.
One of Petes Super C videos

vale tappet settings?broke valve spring can cause this too

My 1950 farmall C has a zenith carb with only one fuel adjustment screw on the carb.

The adjustment is backwards from what you would think. Turn the screw in, clockwise, you make the fuel mix richer.
I have my fuel adjustment screw turned max CCW.
Look at your plugs. If plugs are black you are too rich.
Start with battery voltage when running.
IF someone converted to 12v, it is possible the coil isn't getting enough voltage.

Do a compression test.
New plugs, plug wires, dist cap and rotor.

My farmall has a magneto. When I have an erratic misfire I have condensation inside the mag.
The misfire happens after the mag gets warm and the condensation forms on the top of the mag cap.
I use compressed air and dry out the mag.

Condensation under the distributor cab is a pain in the butt. Condensation caused an exhaust valve to stick on my Jubilee.

Good luck. Keep us posted about what you find.

Thanks for the solutions!, Ill try them today when I have time.

IF you will put a timing lite on each wire starting with #1 then going to the next you will find the spark is not steady which means the bushings in the dist are bad and i bet thats your problem gas problems do not make missfire

I agree. If you can wiggle the distributor shaft up and down, toward the block and away, any at all it is worn to the point of bad timing and needs rebuilt or replaced. Jim

Had the same problem with my tractorAllis Chalmers. After much head scratching and trying different things, I found 1 of the terminals on the coil was loose. The stud for the hot wire would turn inside the coil. I replaced the coil and have not had any problems since. HTH. Avery

ya know one thing here people miss is that no one ever thinks about putting a couple drops of OIL down inside under the rotor button on that FELT so that moves freely . here again i find sticking point cams when i work on them . Yea i even forget to put a couple drops of oil down there .

Take the 1/8 pipe plug out of the intake manifold . Put a vacuum gage on it . Readings will point to most issues .
Quick way to tell what cylinder is missing is take a spray bottle with water and spray the exhaust manifold at cylinder ports . All the firing cylinders will steam up . The one that not firing wont steam up and stay wet .

I knew the adjustment screw was for something haha! Also my tractor is converted to 12v so Ill check that out. Also just to clarify, the carb was purchased by Dennys carb shop because I sent the old one in to get rebuilt (big mistake) because they said the old one wasnt rebuildable or something. But thanks for the pointers

I figured it was definitely ignition but you have to hear it in person to tell that its not a fuel prob

Or this jim