46 B spark problem

When I pull the sparkplug wire out a short distance within the cap opening or just outside of the opening, the plug fires. The spark that jumps from the magneto cap to the sparkplug wire does not seem as strong as the spark for the left cylinder. The tractor will run on one cylinder with the left cylinder. When I try running on one cylinder with the right sparkplug wire, the tractor slowly dies off.

The problem is also rpm sensitive. At low rpms when I have the sparkplug wire sitting just right within the cap, the tractor will fire more steadly but still miss occassionaly; however, when I speed up the tractor, the right cylinder will fire more steady. At wide open throttle I could pull a load and not have a miss very often; slow the rpms down and the miss reappears.

Thanks for any input on what I need to repair/replace to solve this problem. I would guess replacing the C magneto with an X would solve the problem.

At idle on the single barrell carbs, its common for the left cylinder to fire stronger than the right anyway you know. Also, you need to be runnign wire core and NOT carbon ciore auto suppresor type plug wires.

If one side still produces a better spark than the other (with good wires and plugs), the same set of points and coil and condensor produces BOTH sparks (could be a difference in the points gap if rotor or rotor bushings are worn, try a slight gap increase to maybe 0.017), also check the gap on BOTH high cam lobes, if the rotor bushings are worn and the rotor wobbles, that can make an RPM spark difference which a wider gap may help temporarily. If the rotor and bushings and cam lobes check out, its time to look at the caps and rotor and the lil spring & assembly where the outer cap mounts to the inner, and look for cracks or residue or carbon traces in the caps and/or terminals or for carbon build ups or cracks by them etc. etc.

Of course, the points need to be clean and NOT gray oxide coated (if so clean/polish them) and need replaced if they are burned or pitted or carboned up bad, and make sure the points spring or wires to the points are not shorted or frayed.

Duane Larson is very knowledgeable and has good specs and detailed info on those C mags also, but check the plugs and wires and cap and its mount (esp spring and rotor assembly) and the rotor tips and see if that cures the problem.

Good luck n God Bless

John T Nordhoff in Indiana