The 460 in my '83 F350 will just barely crank when warm & may or may not start. I put a booster on it & more juice doesn't help. New starter = no change. Cranks and starts pretty good cold. At about the same time this started, it began (very suddenly) running very rough at low RPMs and will not idle cold. Runs and accelerates just fine at higher RPMs and runs a bit better when warmed up. Has new plugs and wires. I would really appreciate any and all ideas of where to look next.

 

Does the choke work properly?

 

Yes - the choke works fine and I took the carburetor apart and could'nt find any problems. Idle jets are clean and clear.

 

My 300 had similar problems and it turned out to be the distributor moved. Definatley check timing if you haven't.

 

sounds like your timing is too advanced. also check that your battery terminals/connections are in good shape with no corrosion. Check for vacuum leaks and might need a rebuild kit for your carb if it still runs rough after setting timing.