Re: Coming Loose.

I was fighting with this on most 4 stokers...

In spite of conventional wisdom, I fixed the loosening problem with plain old blue lock-tite.

I completely cleaned the threads and receptacle to make sure they were clean and dry.

I applied a few drops of locktite and screwed things down, letting the engine sit overnight.

That solved the loose muffler problem on all of my Saitos.

Re: Compression

You should get a bit of resistance as the prop swings around, assuming the glow plug is in place.

If not, the valves may not be closing fully, and they need to be checked.

This may also be why there is such a difference in the heat you've noticed.