Cub that wouldn't start

Roger46 · Aug 1, 2010

Last week I posted a message about my Cub that wouldn't start after being at the Wisc Farm Tech Days. It had spark, gas, and compression, but would not fire. I finally discovered that it didn't have sufficient spark. It turns out that the magneto got wet inside the coil area as well as the top cap. The only way I was able to completely dry it out was to heat up the magneto with a heat gun and put the top cap in the oven (wife not real happy about) for about an hour. It is an old top cap and must be bakelite as it seems to have absorbed water; because I first dried it with the heat gun, but it became wet inside again after sitting overnight. Also, I discovered that the tang inside that contacts the coil was broken and not making good contact with the coil. Fixing that and drying it out, the Cub fires right up. I was surprised that it wouldn't run with the spark it had, but must not have been enough. I did what someone had suggested and opened the gap on a sparkplug to about 1/8 inch and it wouldn't fire, but my Farmall B magneto would easily fire across that gap. Thanks for the suggestions. Roger

Janicholson · Aug 1, 2010

Clear acrylic lacquer will waterproof the surface of bakelite. Get it dry first. Putting a very minimal skim of rtv sealer on the surfaces that mate will keep moisture out. Jim

Cub that wouldn't start

Roger46

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Janicholson

Well-known Member

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