[AT] Cub problem

[Greg Hass]

Am having trouble with my 1949 Farmall Cub. It sat from fall until about 
April when I started it. It started right up and ran fine for a minute 
or so then started missing and almost stopped a couple of times, then in 
an instant ran fine for a minute or so and did the same thing over again 
and again until I shut it off. A few days later I tried it again and the 
same thing. I worked the garden and the same. I might make a pass or two 
just fine and I will have to stop a minute or so until it runs right and 
then go again. I took the drain plug out of the carb and fuel flow seems 
ok. Choking it actually makes the problem worse. Also the problem clears 
up too fast to be fuel (my idea). A couple of years ago I switched to 
battery ignition; I did not put a whole unit on but fastened a coil onto 
the mag. It has worked perfect until now. It seems as if the spark 
starts following a carbon mark or something and then suddenly starts 
following the correct path. I checked the cap and found no moisture 
inside. I know the plug wires are old but looked in the dark and could 
see no sparks. Most of the problem is knowing if electrical or fuel. I 
am guessing electrical because it seems to clear up and start too quick 
to be fuel plus if starved for fuel the choke will usually help for a 
few seconds. I put points and condenser in when I changed to coil. Any 
ideas.
         Greg Hass