Farmall Cub

Guys
I have been fighting a problem on my dads farmall H for over a year now.
the short of it is I have replaced the cap/plugs/wires/points/ condensor and the plugs at least 2 times. checked the valves at least 6 times. Set the timing another 12 times. all that looks good. Compression was 90,91,91,90 for a 1944 disalite head I don't think that is bad.
I keep getting a miss in this tractor. It will run great for a while then run on 3 cylinders or run on 4 prety crappy. the only thing I can think of next is to try a different dist. I think maybe the bushing are worn out and it is causing a problem. Would any of you have a spare I could borrow to test this out? I would pay for shipping.
Chad

Chad,

I'd be thinking more about the possibility of an intermittent sticking valve. How about trying your favorite elixir in the oil, and maybe in the gas as well?

Try it on the valve stems too.

Bill

Sticking valves. Change the oil then add a bit of Seafoam (or similiar).

Distributor. Sometimes the innerds get gummed up. They are fairly simple to disassemble, clean and relub. Check the weight pivots for wear.

Under the rotor, in the center of the rotor mounting post, on some distributors, is a wick. This wick is supposed to be and is seldom if ever oiled. The wick lubricates part of the advance. Also the points pivot post takes a bit of grease.


Eugene

CJ, check for side to side play in the distributor shaft. if there is any it will change the point opening, and can cause a miss. Another possibility is a crack in the manifold openign and closing with heat changes.

Hey 'CJ'...I had a similiar problem with my Farmall M when I first got it...LOWE & BEHOLD...it turned out to be a BAD COIL (that would short itself intermitently)

ONE NEW COIL...and she was chuggin'along on all 4 GIANT PAINT CANS!

The compression numbers are right one. Can you determine if the miss is random or always from the same cylinder? That would at least separate the engine from the spark maker. Next time its missing very noticeably try using one of those inductive neon spark indicators to see if its missing randomly or from a single cylinder. If its just one cylinder pulling a plug wire while its running won't change anything.
You didn't say if the miss is at idle or under load. I would also time it by ear to see if it smooths up. I had a situation once where after carb rebuild and ign tune up, the tractor still ran real bad missing at random. Finally I loosened the distributor and timed while running at idle and its purred like a kitten ever since.

OK I agree with John the cub owner check for an intake leak go and retighten all the intake nuts, Next are you using solid core copper plug wires,Points clean and gapped at 20 thousands, good autolite plugs champs are not working well these days,All wires are good,NO water in gas,valves set corectly cold and hot. I would check these things before I try another dist . On second hand I would throw a mag on her to try instead of a dist to see if its the motor or electronic.
JON
http://www.farmallmagneto.com

Guys lots of things to try. I have tried 3 different coils. so I doubt it is that. Yes soild copper core wires. all champion plugs but many different sets. I think it is one cylinder but yet It seems to move around. some times when it warms up it runs better and it doesn't matter if it is high idle or low idle. once in a great while it seems like a gas problem like if you choke it for a quick second it will run good for a few seconds. I am getting fouling on the plugs that are not firing. I guess I have to do some more fidiling when it warms up. I will check the intake becasue it is a used engine we put in there and we did have to bolt our intake manifold. Maybe it is loose. Thanks guys!

Magman I would love to put a mag on it but I don't feel like taking the one off my dads farmall A and swapping it out.
Chad

I noticed when I first took off the original manifold on my H that the exhaust holes were carboned up real bad. Might give the manifold a good look.