Re: Lapping flywheel to crank taper?

[Don]

How well I remember those soft metal flywheel keys when I worked on the lawnmower shop as a kid! It was very common for the homeowner to hit something and shear the key causing loss of spark…The nice thing about the Briggs was that shearing the soft key rarely damaged the flywheel or tapers, whereas the Tecumsehs usually wrecked the flywheel when their solid key sheared. Now that most mowers have breakerless ignition, they don’t lose spark when the key shears….So, I’m thinking that many strange running conditions don’t get easily diagnosed.