F-20 Runs Rough

Anonymous-0 · Aug 4, 2013

I have a 1938 Farmall F-20. I have taken the carburetor completely apart, soaked it, cleaned it again with carb cleaner, blown it out, checked the float level, replaced a cracked tube which goes down into the bowl, and put it back together and it still runs rough. When I turn the two adjustment screws(Idle & main jet) in and out, they do little if anything (same as before). The fuel bowl is clean, and I recently placed an in line filter between the bowl and carb. Also, years ago, this engine had the pistons replaced with the 1/4 oversize aluminum ones, and had the power carb kit installed. It also has a Wico Conversion Distributor installed (my dad installed this after it kicked and broke his wrist). Any idea why the engine still runs rough after doing the things I listed above? Could it be a spark plug issue?
thanks,
Lou

clint s · Aug 4, 2013

Far from an expert and more will chime in hopefully. Did it always have a fuel filter on it. On gravity fed systems sometimes a filter can be too restrictive to let fuel through especially when plugged up a bit. Had it happen once on my 200. Changed to a different filter and it was fine.

Ron W · Aug 4, 2013

Check your firing order. 1-3-4-2. Make sure the direction of the rotor matches the direction on your cap. Also, check your timing with a timing light to make sure you are not too off on advance or too retarded. That will make the tractor run rough.

I have said it before, a properly timed magneto will never kick back; I have never had a farmall kick back that I have timed or check timing on. Now for FORDS....I have scars from Model A and T's that bit me.

EM Iowa · Aug 4, 2013

Check to see if you have a steady stream of fuel going to your carb (use the drain feature on the carb), and if you do have a steady stream then it may be a distributor problem. Has the valve lash been set?

Tom Fleming · Aug 4, 2013

Well, there are a lot of things it could be, so let's start with the basic stuff. A bad condenser will cause rough running. Are your wires copper or graphite core? Are the points clean? Are the plugs fouled? Are you getting good air flow though the air filter? When was the last time your oiled the valve train? Do you have sticky valves? Are the primer cups shut tight and/or are the primer cup holes plugged?

Let's start with those, and move to the next set of questions if those don't ID the problem.

F-20 Runs Rough

Anonymous-0

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clint s

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Ron W

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EM Iowa

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Tom Fleming

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