A year later . . .
Put in a new Perry Pump. Went back to 5 shims. Switched fuel from Cool Power 15% to Omega 5%. Tuned Pipe backed out.
The goal was to lower compression.
It now runs like there was nothing ever wrong with it. 2 Tanks. This was it. If it failed I was giving up.
17 x 8 prop 8400 - 8500 RPM. I really need around 9300. The tuned pipe will add about 300 - 400 RPM.
So I will start testing by removing shims 1 at a time. This will increase compression. Will/Should it increase power?