deerhunter,
MTD are the follks who own Troy Bilt. I have heard and I could be wrong that Zenoah and Honda had a little bit to do with the development of there newer 2 and 4 stroke engines.
below is the lonk to the MTD site:
http://www.mtdproducts.com/corporate/index.jsp
I have converted One of there 29cc 4 stroke so far it looks promising.
Honda didn't have anything to do with the
Mow
The
Driveway machine, neither did Zenoah which is now owned by Husqvarna