APC 14x6; stock unmodified muffler; has about 10 hrs of running; 2.5 gallons of fuel; 62 degrees F; alt 3000 Ft;
Mach-7 15% nitro; oil: castor/synthetic blend; OS A5 plug (#10). 10770 rpm. Engine does not seem to be
running good. Tried OS#8,#10,#6,Fox long with bar. Runs best with #10; worse with #6.