Re: racing engine

[David Stanton]

Many props have a thin rubber piece between the hub and the rest of the prop for shock absorbtion if you hit something. When the rubber ages and starts slipping, it does exactly what you described. Sometimes you can’t see that the rubber is even there. To check for this, take a permanent marker and make a mark from the prop to the hub. Then run it until it revs, and see if the marks are still aligned. There are places that can repair this problem, but on small HP motors like yours, it’s usually cheaper to buy a new prop at a discount place like propcopropellers.com.
Dave