1949 Farmall Cub choke run

[Charley1c10]

Hey everyone,I appreciate the add.Ive been helping my grandfather on a 1949 farmall cub.Ive worked on quite a few vehicles but this is the first tractor.He said it was boggin under load when we started and then wouldn't crank afterwords.We opened the distributor cap and cleaned leads and did plugs and wires.Fired right up with the choke on and ran like a champ while the choke was on until it got good and hot then you would have to cycle the choke on and off to keep it idlin.We changed the gas bowl and cleaned the carb,still did the same thing.I sprayed ether around the carb to see if we are getting air anywhere while it was running.Came back a month later and now wont crank.Sorry for the book,just really could use some experience,advice ,anything you could give on this.Thanks

[chuck ma]

Charley You said you cleaned the carb, did clean and blow out the little passages in all the jets. I found it to best to disassemble the carb completely and let it soak in carb cleaner or lacquer thinner over night, then use small brushes or copper wires to clean out all the passages and reassemble. Pay attention to the position of the choke shaft yoke when mounting the carb on the tractor. There are pictures on here the show you the correct position of the yoke just search for them. Be careful disassembling the carb halves, lift strait up, to avoid breaking the tube inside. Chuck

[chuck ma]

Charley you say won't crank, by that you mean battery won't turn the engine over or are using a crank to start it and it won't move? If battery is used and and can't get the engine turn over. First thing is check battery voltage with a meter should be 6-6.6 volts on the meter if its a 6volt battery and 12 - 13 volts on a 12 volt. next clean and check all battery connections shine up good with emery cloth and wire brush. If doesn't help check voltage to the coil and out of the coil if so equipped. On a magneto ignition I'm afraid I can't help as I have no experience with them. Also check contact on the saddle switch located on the starter.
Chuck

[Glen]

Hi,
You could try cleaning the main jet on the carburetor, it might be plugged and need cleaning.
In the post below is a post by Barnyard, showing where it is, and how to clean it.
The info is for an IH carb.

viewtopic.php?f=1&t=103549

There is originally a small screen at the gas tube connection at the IH carb, clean the screen, if you didn't.
Tighten the connection and everything on the carb gently, the carbs are soft metal, and threads can strip.

The ignition points could be burned, and need replacing, if they haven't been replaced for a long time.
Test the spark and see if it is good. There should be a strong blue spark. Remove a spark plug wire from a spark plug, and hold it with the end of the wire 1/4" from a bare metal place on the engine, and crank the engine over, with the ignition switch on.
A yellow spark is weak, and needs improving.
The Cub operator's manuals show the ignition points, and the point gap.
TM Tractor at the bottom of the page has new points and condenser.