Farmall Cub Carb Question

DM0180#

New User
Hi, picked up a 1948 Farmall Cub this morning, it turns over and is getting fire to the plugs, however it will not crank. One question is when I take the drain plug off the carburetor, it will continue to drain gasoline until the gas tank is empty. Does this mean my Float is hanging in the carb? Should it continue to drain gas like this?

thanks for the help
 
Yes it should, when you removed the plug you drained the carb and the float was trying to let it refill.

Since this cub is new to you I suggest the first thing to do is make usre the magneto (if still original) or distributor (if magneto has been replaced) is firing #1 plug when #1 piston is at top dead center. Do not rely on the timing mark to for the right cylinder, check by removing spark plug to verify it is the right plug
 
You say it will not crank . Do you mean it will not turn over or it does not start. If it will not turn over I would start with connections from the battery and voltage in battery. If it turns over then like John said check timing and fuel supply even if you have spark if it is not at the right time it will not start.
 
Ok guys thanks for the help. Forgive me if this is dumb question but I am young so be nice. It is turning over, and I removed the spark plugs from the block and turned it over, and they are sparking with a white spark. I am hesitant to think it is a timing problem because would the timing of the spark go bad from sitting? If the man I bought it from can be believed, it was running fine when he parked it two years ago. Two years of sitting makes me think that it is a fuel problem. I am cleaning out the carburetor now and bought a rebuild kit from Tractor Supply, so I am hoping that may fix it. Again, the question is would sitting for a couple seasons throw the timing off for the spark?

Thanks again
 
Just setting would not, but it is amazing the number of mechanical problems that mysteriously happen to tractors just setting. Most of them were parked for a reason. Stuck valves will prevent it from starting, especially intake valves. Have you done a compression test, or used a hand crank to turn it over by hand? Turning it with a hand crank it should have compression twice per revolution.
 
Assuming you have an IH carb, remove the small plug on the side, and attached to the rear you will find a brass tube that is the load jet. There is an orifice in the end with a tiny hole in it. Make sure that hole is not blocked. A very small copper wire such as used as in home telephone wires is good for clearing it.
 
I am located in Upstate South Carolina. Tried rebuilding the carb and blowing everything out, also put in new plugs and it is still not
firing more than once or twice. It is trying, not sure if a valve is stuck or not but it seems to turn over without too much internal noise.

Back to my day job for the week, may try to take another crack at it next weekend. Attaching a pic of it (hopefully)

Thanks again


cvphoto12514.jpg
 
Take the muffler off, pull the choke out, and crnak it over a few times, then see if you can smell gasoline in the exhaust pipe. If yes, check the ignition timing, including #1 plug firing when #1 cylinder is at TDC, especially. if you have had distributor off, it is very easy to get back wrong.

If no gasoline smell check fuel delivery, including bad or missing carb-manifold gasket, etc.
 
(reply to post at 20:42:33 02/11/19) :?: Okay, my 2 cents worth. You state the ignition fire is white not blue?
IF tractor has distributor? (Maybe I missed that part somewhere)
Be sure to clean the point contacts. You can use 400 grit wet dry sand paper or a burnishing file, which looks like a narrow fingernail file. It actually cleans point contacts better.

BE SURE to go behind with contact cleaner or brake cleaner on edge of clean shop rag and clean contacts of any sanding debris.

VERIFY point gap, ?.012-.016", about the gap of folding matchbook cover at the widest opening.

Points will become poor connections to ground after sitting for time, such as this tractor. Have delt with this, on many point ignition systems, back in their day & presently on yard ornaments.
 

We sell tractor parts! We have the parts you need to repair your tractor - the right parts. Our low prices and years of research make us your best choice when you need parts. Shop Online Today.

Back
Top