Don't know about thrust, but if you're five turns out and have to adjust the throttle to go lower than 7000 then you aren't getting it rich enough. With a Perry pump mine is 1-1/2 turns out for flight, and turned a Top Flite 18x8 at 8800 RPM. Since then I installed a Zinger 18x6-10 which performs better. You should be able to get the thing to die by turning it out 5 turns. 9000 might be possible on certain props.