If you run the P80 for long the big black carb
will loosen up and may fall of.. I sugest
glueing the carb in with loc tight.

I have had many many P80s because I lived very close
to Tidewater inc in Bastrop LA, where they imported, modified
and raced them in boats... (same motor)

I was getting them for about $100 new and ran them on
every thing from Byron, Ramtec to 10x8 props turning ~17000
I tried a 10 x 6 prop but it flung it apart at the hub...
I think some of the prop was going supersonic because
of the very loud noise it made...

I too could not get it started unless I loosen the glow plug..
oh well..

Run some 20-30 percent and it will run better..
Change the carb to OS and will be better still..but the
black one are fine..

hope this helps.

Eddie Weeks