Thread: Prop Advice for a 115hp 4 stroke

4 blade will give you more hole-shot and midrange power but your going to lose some top end. What RPM are you currently running WOT.


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Eatin ain't cheatin

I have a 19p stainless 3 blade if your interested in a trade for the 17p. PM me if your interested.

I ran a 21 p stainless three blade on my 115 Yamaha four stroke ......18 and a half ft. G3 Eagle185 boat and it worked great.

Originally Posted by Uncle BS

I have a 19p stainless 3 blade if your interested in a trade for the 17p. PM me if your interested.

I sent you a PM on a trade

Originally Posted by "G"

I ran a 21 p stainless three blade on my 115 Yamaha four stroke ......18 and a half ft. G3 Eagle185 boat and it worked great.

I just won an ebay auction for a 3 blade 21p stainless steel Solas prop. I plan to try a few out. With my 17p I am running 6300rpm

Your RPM with a 17p aluminum is just about perfect for you engine. Going from an aluminum to a stainless you usually want to drop down 1 or 2 degrees of pitch to maintain the same RPM due to the limited flexing of stainless and more cupping. A 21p stainless is going to be way too much pitch for you set-up. I would suggest a Powertech NRS3 in 16p or a Turbo 1 in 15p. They only make the Turbo 1 in odd pitches for the 4.25" gearcase and it's going to have a little more rake and cup than the Powertech so the 15p should keep you in about the same RPM range. Just remember each degree of pitch you go up or down is going to affect your RPM by approximately 200 RPM. Also, going from a 3 blade to a 4 blade of the same pitch will have the same effect. That 21 pitch is probably going to drop your RPM about 1000 which is not where they Yamaha four stroke needs to be ran. Hope this helps.

By the way, just changing from a aluminum to a stainless should have a positive effect on your performance as long as you keep it in the proper RPM range. Stainless props will have more rake and cup and won't flex like the aluminum props will. Thus, they will provide more lift and better overall performance.

I know it wasn't meant for me but its info for All! Slab junkie, Thanks for info on aluminum Vs stainless!!
Been doing some reading, and had not read that anywhere! ( but it makes very good sense)