The Homelite 25cc is no dog really. It can be modified to turn a 16 x 8 prop at 8700 plus rpms.

I have made a lot of posts about Homelites over the years. You might find "Non machine shop Homelite" interesting, among others. Just do a search for my posts here in the forum.

Here's one: http://www.rcuniverse.com/forum/m_26...tm.htm#2621860

Have fun with it.
AV8TOR