I have the Hd 4000 kit ON MY O9 35 HORSE I have about 37 hard sand and mud hours on this motor. It seems now that I have no hole shot and top end is week. I kept thinking it was the mods I put on I adjusted the carb put a bigger main jet in thinking is was starving for fuel and nothing seemed to get any better, but now I think It might just be the prop. How critical is it to have it at the 12.25 im down to about 11.5 tip to tip is this were my problem is. I just thought a prop would last a little longer but I do run in alot of sand

Sand will eat your prop up in no time. If it only measures 11 1/2" tip to tip than that is your problem.

Prop wear really effects the way these surface drive engines run. Bring it to your local prop shop and have em fix it up for ya.

I kinda figured thats what was goin on because Im gettin alomsot 4250 rpms but im not gettin the speed wihch was telling me the prop is spinng that fast but the cupping is gone to push me forward. I see mud buddy has their tiger props on sale is that the best big blade to go with or are their better props out their. Thanks

Thanks for the help this site is awesome at gettin your questions answered fast.