Just a thought, new engines can be hard to start, and a lot of times will only run a few seconds at a time for the first few starts.
I had a student with an O.S. FP 25 that almost gave up because of this.
The engine was very tight, and though he had the needle valve set right, it would start and run just a couple of seconds, as if it were to lean. He would then richen it and flood it, and ruined his spinner too.
After a 1/2 hour of BREAKIN, it was fine, and he is still flying.
A burned spinner is your least of worrys at this point!
DON'T GIVE UP!-GET SOME HELP!

Jetts