How do I know what kind and size of prop to use??

Question

Any ideas on what style or size prop to use on a 1967 Johnson 9.5 hp?? I had the issue with the gas earlier and now fixed that with proper gas/oil mix. I still think that the motor could push higher rpm,s, Let me know!!

Answer 1

It's only a 9.5 there are only maybe 2 props sizes for it see which1 you have> The lower the pitch the higher the RPM

Answer 2

The only way you will know if it is revving to max rpm at WOT is to put a tach on it.  Usually the prop that comes with this size engine is pitched for all around use.  Unless the boat/load that you are pushing with it is unusually heavy, my guess is that you have the right prop on it now.  If you have a very heavy load to push, reduce the pitch 2 inches and you should be OK.  Good Luck!