That mower engine might be useful to somebody wanting to build a small hovercraft.
https://www.facebook.com/hoverclubofamerica/
There is a Yahoo user group called ecycle(
your city name) that people post things for free. That is how we got our lawn mower and other yard tools. They were only about a year old, people were getting out of town ASAP and just giving all sorts of good stuff away for free. This was about 15 years ago, mower still works flawlessly.