1936 Model B w/ Wico Type C Magneto

~First take an old [known good] spark plug & open the plug gap to 3/16", then install that in one wire at a time & lay it on the block. Then crank the engine & look for a nice BLUE spark to jump that gap MULTIPULE times in a row. If you get a good blue spark [more than one] at that 3/16" gap there is nothing wrong with your mag.

~If no spark, try the 3/16” plug & a wire directly from the center coil output tower [if spark there & not from the wire towers suspect a cap or rotor problem].

~If you didn’t get a spark, MAKE SURE the contact clip between the inner cap & coil contact button is contacting the coil button [a common problem on the C mag].

~If you don't get a blue spark, start by listening to the mag as you turn the engine over, "does it snap when the engine is rotated?" ..If not you have an impulse problem like rust on the impulse levers, or a broken spring, or tight cup.

~If it snaps, then make sure it snaps when the L/H impulse on the flywheel lines up with the case mark [at 3 o'clock behind the flywheel.

~If it snaps at the correct time [or close to it] then you have other internal problems…

~On to the inside…start with the points [just because they are new doesn’t make them good] clean the point contacts of all oil & oxidation, then make sure the condenser is connected correctly & isn’t shorted. If there is an additional wire going to a shorting stud make sure that wire [or the stud] isn’t grounded [or just remove the wire for now]. If you have an ohm meter place one lead on the case to ground it & the other on the points stud then rotate the mag & see if you get a resistance change as the points open & close [if not you have a wire or something else shorted to the case, or the points aren’t making a clean contact].

~If there is any rust on the coil iron core remove the core & clean the rust, then check the magnetic rotor & laminations for rust [if found clean the rust off]. Check the coil pig tails for proper connection to the points & make sure the coil ground pig tail is fully grounded.

~If nothing found so far it’s time to pull the mag from the tractor. Once off the tractor rotate it slowly & feel for a resistance as the internal rotor magnets line up [if no resistance spots found suspect the rotor has lost it’s magnetism].

~Try to move the rotor sideways to check for loose shaft bushings [if movement found, replace the mag bushings] OR, open the points gap to .018” & re-try to get a spark [you could even try that before removing the mag from the tractor].

~Try some of the above & post back with any questions….

Is the mag 'tripping' at impulse mark on flywheel? It has to give out a solid thwak sound at hand crank speeds in order to deliver sufficient spark.

Are the points gapped to open 0.015 on high cam??

Did you get the new coil wired correct with its ground wire and other wire that goes to the points???

Does this mag have any kill switch???

When you do the plug tests, are the wires and plugs good and them against ground and when the mag is rotated when she snaps, they dont fire at all????? ????? ? Will the wires end itself (dont use plugs) jump a spark to frame independant of the plugs?????

Be sure the wires or wires to the points (one of which is from coil, another from condensor, possibly a third to a killer) are not grounded or shorted or gettign to ground anywhere, AND any kill switch or wires to any kill switch ARE NOT GROUNDED. If the points are permanently grounded by any wires or switches or studs etc, it will NEVER fire.

OKAY, if the points open and are gapped correct and theres NOOOOO O grounds or grounded out or shorted wires etc to the points, it could possibly be a bad or shorted condensor, even if its new. Be sure the condensor wire is not shorted out anywhere. Test the condensor if possible, but if you cant, you can remove it and see if she then sparks????? The spark wont be very good without it, but it will still spark, and if it sparks with out it but not with it in, its probably BAD. Try her with the old condensor see what happens.

I guess youre aware that at slow hand crank or starter speeds the rotor dont spin fast enough past the coil to produce any spark at all????? ????? ? so a spring has to wind and trip to whirl it fast then. When you turn the mag, does it produce a sharp loud snap each 180 of rotation???? If not, it will NEVER spark at cranking speeds, but the tractor could pull start cuz once over 250 RPM, that spring wind n trip assembly are not operating. Will it pull start and run okay now????? ?? if so and when you rotate it slowly it either does not snap loud and sharp or only makes a dull clunk, the wind and trip assembly or the spring itslef may be bad. If the trip dogs are not engaging, sometimes a cleaning and light lube will make her work and wind and trip again. Take the mag off and on the rear when you turn the coupler CCW, the dogs should come out and engage and wind the spring assembly and she will wind n release n snap over sharp each 180.

To see if it has any spark with the cap removed (to eliminate any cap or rotor problems) you can have a wire atatched to the mags metallic frame and then placed within 1/8 away from the coils high voltage output button/terminal and each time the mag snaps and fires (every 180) a blue spark should jump there. Again, if she never winds and trips the spring to snap over, she will never fire.

I guess the cap is assembled correct and the coils high voltage output button/terminal is attached to feed out the high voltage????? ?

Try this and post back what happens and answers and I will try n help you more.

John T Nordhoff