Replacing Magneto Seal
The cub still was not running right. When I had it apart before I had
installed a new seal but when I removed the magneto again I found it
full of oil. I thought I must have damaged the new seal but it was not
hurt. The old seal was dried hard and cracked, I don't know why it
didn't leak. If you look close in this photo you can see how the old
seal had worn the surface where it rides. Towards the gear is a area
about 5/16 that is not worn at all. When I installed the new seal I
put it in the 23/32 that the book said. This puts the seal flush with
the inside of the casting. I was hoping the new seal would work and
take up for the wear. But no luck with that. If you look close in this
photo also you can see the timing dot on the end of the gear tooth
painted white.
In this photo you can see that I painted the timing dot that is in the
gear valley and the top surface of the gear teeth each side of it.
I made a wooden seal driver about 1/64 inch smaller in diamiter than
the seal. I had to cut a creasant out of it to clear the ideler gear to remove
the seal with out damaging the seal.
I removed the seal before reinstalling the govenor. That made it a
breeze to get the gears lined up right. Then I reinstalled the seal
using the driver I made but that would not put it all the way in due
to the end of the govenor gear protruding towards the magneto drive.
So I ground a fiew thousand of a inch off the old seal and used that
as a spacer. I put the seal in 29/32 of a inch. That puts the seal
lip on the unworn area of the govenor gear by 3/16 inch. That leaves
a little more than 5/16 inch of the seal in the block casting.
I turned the engine over by hand to make sure it was not touching
anything. There should be no stress on it. Now all that is left to do
is to take the magneto all apart and clean the oil out of it.
