all good info,,just for chits pull off the hose going to the front of the blower and see if theirs any fins left on the blower..

Save a lotta time, get a new tensioner and belt. Been there.

you swapped blowers and carbs and it made no difference, sparks not dropping, valve float

I cant see if being valve float at 5300, unless you had valve springs from a flat tappet 330 Merc in it. lol

Check the tensioner operation. Also, You may want to add a idler pulley.

[youtube]http://www.youtube.com/watch?v=XJ1I_NtxVK0&list=UUoyUg1bQZ8ptd9AKYkI_M3A& index=9&feature=plpp_video[/youtube]

We might go out one more time. Going to put a new belt on it and tighten up the tensioner. If that doesn't work check the springs. The blower looks perfect switched them from motor to motor and that motor still has the same problem.