This is a Hartman starter nut for the flywheel side of your McCulloch motor. If you are running your mac motor on the left side works great for left hand starters. Works great on rear engines karts too.You can use a 5/8 socket or 5/16 allen to start it . It bolts right to your flywheel.This is a original used one.
Vintage Racing Kart Hartman
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