BARCC:
I usually don't respond to OS threads, but it looks like DaveH, FBD, and W8YE are off somewhere else. Along with all the rest who might give an answer.
1. My .91 FX is Rich, but it is hot when i touch the head after running it,
Even with a rich run, 200F is not excessive. Up to 250F is still OK. 275F is getting to the dangerous point, specially if you're not using castor oil or a castor blend. Back when I was running C/L speed we'd let the engines run around 350F with pure castor oil.
2. My .91FX Makes a "click" sound after the piston goes up near the head after the engine is run.
On this one I'd pull the back plate and check the connecting rod. A loose fitting rod is about the only thing that will cause a click in a two stroke engine that runs fine otherwise.
3. My .91FX has less compression than my OS .50SX, is this right?
Perceived compression is dependent on many things. Among them are the size of the lever you use to turn it (the prop) and the port timings of the two engines. If the 91 has 91 power the compression is fine.
Bill.