A plastic screw top off a Coke bottle is just about exactly the right size and thickness to slip over the switch button and adjust the engagement point between the mechanical linkage and the "motor run" point. If you look at the pivot point holes and the rod that connects the pedal linkage to the starter bell crank, I'll bet you're going to find some wear and elongated holes that are wasting a little of the travel.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!