RE: US Engines 41 Starting Procedure
I'd just like to add that after no less than 7 flights, the spring starter on my US-41 balled itself up, exploded the roller bearing, and ate up the central post inside the spring.
There seems like there might be something going on because numerous people I know have had similar problems with theirs. Luckily the US Engines people are good people and less than 3 days later I got my new spring starter kit for no charge.
P.S. You can't start this engine by hand. And indeed you can't start most magneto engines by hand. They need that extra oomph of the spring. I "choked" mine by just pumping a few pumps of fuel straight into the carb. For a brand new engine, it started and ran remarkably well!
P.P.S. I ran my in the cowling of a Top FLite P-51, and I took the carb venturri off. Looks much cleaner this way, and it hasn't affected performance at all. As a side benefit, the little bit of fuel the carb spits out occasionally flow right past the exhaust stubs of the full scale engine on the cowling. Natural weathering!