Re: Project: "Sweet 16" Update; ignition Help

From: Michael Frenn <semsc@...>
Date: Wed, 27 Jun 2001 13:36:34 -0700

Okay, here is where we are to date.....

Removed the magneto and examined the cap, rotor and points. The points were
very badly pitted and needed replacing. The cap was marginal, and may have
cleaned up with some filing. Not worth it as part of a refurbishment.

Learned a very important lesson: Do not pull on anything!! The plug wires
screw in to the cap. Fortunately, the one wire can probably be fixed.
However, when removing the coil, do not pull on the little metal button to
get the coil out! Probably will have to replace the coil :(

I still am a little confused on something. There is a black/white wire from
the key switch to a post on the side of the magneto. From that post a wire
goes up to the points. On the other side of this post (inside the magneto),
a wire comes from the coil. This post is very carefully insulated on both
sides. I assume that the coil generates voltage (from spinning magnets)
that it sends to the points via the post an wire. When the key is turned
off, the black/white wire provides a direct to ground circuit, killing the
magneto. Why, then, if you measure resistance bewtween the post and the
power head withthe key in the START position, there's a direct connection
ground? Actually, I know why you get this result, the coil has two wires,
one to the post and one to ground. The resistance through the coil is 0
ohms so the post is grounded. The reals question then is, is the coil bad?
Or is this a normal result and this grounding goes away when the coil
generates current? In othre words, as soon as the motor is cranked, turning
the magnets so that current is generated, do the electrical characteristic
of the coil change?

I'm sure ome of you out there are going "Who the heck cares?!" Well, if I
know how things work, then when I get stuck out the middle of BFE I might be
able to fix it. Also, when talking with the shop guy it helps to have some
idea of what you're talkin' about.

Can anyone shed any light on this?


Michael Frenn
Received on Wednesday, 27 June 2001

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