Re: checking out magneto on Jd A

Posted by Robert on October 21, 2003 at 08:56:49 from (66.250.5.14):

In Reply to: checking out magneto on Jd A posted by JIM.F on October 20, 2003 at 08:25:04:

I guess, the first question is, are you having magneto problems now? If so, what kind of problems are you having? There are several things that you can do without removing and dismantling the magneto, which MIGHT give you the spark you're looking for.
What type magneto do you have? My '45 A has a WICO X, so that's the one I've had some dealings with, but the principles of operation would be similar.
First, with the plugs out,and laying on the block, turn the flywheel over by hand, and listn for a distinctive "snap"--that would tell you that the impulse coupling is working. Also, look at the plugs and see if there's any spark---when that impulse spring trips, you should see a fat blue spark jump the gap (.030) on the plugs. The left cylinder wire is normally the top and the right plug is the bottom wire coming from the magneto.
Your wires should be the wire core type, NOT the automotive resistor type (carbon fiber variety).
If there's no spark, or weak, then, take the cap off the mag and check to see that the point gap is .015 when the arm on the points is on the high part of the lobe, and that the points close completely when the actuating arm is on the low part of lobe.
Make sure the magneto cap is clean, the rotor is clean, and that small coiled spring inside the cap is extended far enough to make contact with the metal button (coil output) on the coil. Also, that the "arm" coming from the spring is extended far enough to make contact with the rotor.
Another tip, is to take a paper clip, and attach on end to the magneto case, and bend the other end to within 3/16" of the coil output to see if you have spark there. It should be a nice bright blue. If you have spark at that location, then the problem is getting the spark out to the plugs--- rotor, contact points, plug wires, plugs.
Hope this will help!

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