Figuring Prop Pitch?

[igh7070]

Ok is there some way of figuring correct prop pitch vs weight of boat ang gear. Is there a formula for figuring this?
I have a 15' V bottom boat with a 35hp johnson on it that I have set up for bass fishing. i need to get a new prop and want to make sure I get the right pitch. I bought the motor seperate from the boat and am sure it is not pitched right for my boat I think the motor came off a pontoon.
Any info would be great thanks.

 

[pootnic]

Re: Figuring Prop Pitch?

theres probably a formula to get you close in proper pitch but the best way is to know your rpms at WOT.
I'm going through the same thing,i have a 40hp on a 16' modV.The 40hp came off a heavier bigger boat,he used a 12 pitch on it.I just bought a tiny tach and plan on installing it today maybe ill get the boat in the water so i can tell you my rpm.That will get you in the ballpark,you will need to get ahold of a tach (or the exact setup) to find out your proper pitch though.

 

[Silvertip]

Re: Figuring Prop Pitch?

There are all sorts of prop calculators. Just Google "prop calculator". You enter the engine rpm, gear ratio, speed, use about 10 - 12% slip and it will calculate pitch. Without any of the numbers you can't use the calculator.

 

[tjl76evinrude]

Re: Figuring Prop Pitch?

i looked on ebay. searched for my size prop and found pics of what looked like mine and had the pitch listed. confirmed it a few times from a few different auctions.

glad i did since i was wrong on my guess.

 

[pootnic]

Re: Figuring Prop Pitch?

hooked up my tiny tach today and gave it a try...grr...sorry i cant help ya,it said i was idling at 1850rpm and my WOT would have been over 9999rpm....must of received the wrong one

 

[mpsyamaha]

Re: Figuring Prop Pitch?

divide those numbers in half... you have a waste fire engine