oh im sorry ralph.. it feels like it has ok compression, however, my tower hobbies starter will spin it pretty fast when it is hooked up to a large 12v battery. it has to have decent compression to spin the props in that rpm range, also i just meant that when i lean the needle out slightly that is when i get the highest rpm.. and the 6000 figure is with a 15x10 the 7200 was with a 15x8 but it seems like a jump so little as 2 numbers in pitch shouldn't change that much, i think the engine is just wearing out and a new ring should help that.. what do you guys think about that much of a drop in rpm just bc of the pitch?