Best prop for 1969 Evinrude 9.5 Twin Sport

[dukekas]

Been looking at calculaters, pitch, pulling my hair out. Is the gear ratio standard, and what is it. Need slightly above the middle towards speed. 10 ft flat bottom.

 

[steelespike]

Re: Best prop for 1969 Evinrude 9.5 Twin Sport

If my math is right I believe ratio is 1.76 ,13:23.
standard prop in 69 was 8 1/4 X 8. I would suggest a tinytach and run it with the
8 1/4 X 8 see what the numbers are,gps speed would be nice too. The hp is developed at 4,500 range is 4,000 to 5000.Most suggest propping close to the top.I have a feeling your way over the rating for the boat.

 

[dukekas]

Re: Best prop for 1969 Evinrude 9.5 Twin Sport

HP wise, I know, it has a 7.5 on there now and is great. Easy to start to. I have a 14 foot flat bottom I could use it on as well. Im over hauling the engine. So keep it stock, there plenty of power??? for those small boats.