....I run one of those engines, and it took a long time
to break in. Is it super tight at TDC ?
It might even "knock" when you first start it up. You
want to bring that engine up to operating temp as
quickly as possible, and run it wide open at a perfect
needle setting....not too rich, not too lean.

If you run that thing blubber rich on the stand, your
wasting fuel. If you have alot of black crud coming out
the exhaust....run it all the harder. Trust me on this.
I wasted a lot of time and fuel "babying" my motor, and
it took about 15 tanks before I got the black crud out,
and it really started to crank. (14K)

I tried a few different props, and found the 11-7 1/2 MAS
to work the best. Be sure to balance the prop, spinner, and
backplate if you want to get everything out of it. Take the
muffler apart and lock-tite it real good before you run it.

Your gonna love that motor....it's the best kept $100.
secret in RC.

Dave.