Whats the right prop

[stetsen]

Would anyone happen to know the right prop size and pitch for a 63 johnson 75 hp Model #V4A-15/V4AL-15. The one on it now is a 10" which im sure it the correct size (not much room for anything else between the prop and plane plate) but I think it has the wrong pitch, It says 9 1/4, not sure this is the right pitch for the boat. Its on a 1963 Sea Ray 700.

 

[steelespike]

Re: Whats the right prop

The motor has an odd gear ratio 1.15:1 so the props are small in diameter and pitch. came with a 10 1/4 X 10 with exchange for 10 X 10,10 X 11 and 10 X 12. Your selection would depend on your boat and the typical load and activities.
If it has a prop run it and get us the info asked for in "read this first" at the top of the prop forum.

 

[stetsen]

Re: Whats the right prop

Most of the info is in my first thread. The issue I am having is not enough speed. I can only get like 10 to 15 MPH (full throttle). Dont have any Idea of what the RRMs are. There is not a gauge for it. Even though the boat weighs 785Lbs and is 16.5ft I would think that I would be cruising much faster at full throttle. Would a smaller pitch prop be better. I know it would increase my rpms on the motor and take a less bite of the water but will it give me more speed. Would love to get this baby up and going so my kids can ski behind it.

 

[steelespike]

Re: Whats the right prop

There is more going on than a prop.First place to look is the motor.
Is the throttle opening all the way?Is the timing set right and advancing as it should.
Is it running on all cylinders.You wouldn't be the first to not know yopu were missing a cylinder
except for the poor performance.
I believe that has a magneto distributor and cap and rotor are expensive and hard to find
and could be worn out.Hope not.