Yamaha F115 on FD226f OB -- upgrade to Stainless Steel prop

Pathfinder22

What size prop did you upgrade to?? Factory Yamaha aluminum prop is 13 1/4 x 17 and while it pushes this rig pretty good I'm cannot get run to Max RPM of 6k. Plus I am not a fan of Aluminum props for use in salt water here in S FL. Thinking dropping down to a 16 pitch standard 3 blade stainless steel will be ideal, and want to know.:

a) should i stay w/ 13 1/4 diameter or go larger? 

b) should i drop to something less that 16 pitch, in order to rwch max RPM while still keeping good crusing speed/economy?

Suggestions are appreciated!!!

FWIW - Yamaha SS props for F115 are available in either 13 1/4 or 13 1/2 dia and either 14 or 16 pitch... 

FlyingV5

Pathfinder, the tech guys on this forum can probably tell you just what prop to try. I expect it will be a 3-blade  due to the fact that 115 is not a lot of horses for that boat. What you want is to just achieve top RPM (either the listed 6k or the rev limiter, as you please) trimmed out on smooth water with the lightest load. At the point where adding more pitch drops the revs, that is too much propellor. That balance point between over-reving and loading it down is your rig's maximum speed. If the recommended prop doesn't let it rev up under those test conditions, maybe your dealer will let you try one with a bit less pitch? If I was buying a prop would definitely go for SS. Also test how it pulls with a full boat. I was considering getting a bigger than stock prop for my boat until I ran with some weight aboard and saw how much the max revs dropped.

Pathfinder22

Thanks FlyingV5. This is for my parents new-2-them FunDeck, and I was try'n to eliminate prop trials based on someone else experience w/ this hull & engine. On my boats, I did prop testing of PowerTech props for the builders, however the hull/engines were/are completely different. I suspect a 13 1/2 x 16 will be the one. But I'll wait to hear from others here. 

FWIW - the F115 pushes this hull pretty darn good, unless ur a speed demon. I've run it ~26 mph at slightly higher than 5k rpm's and it cruises along perfectly. 4500 to 5000 rpm's puts you between 23 and 25 mph. I've also had 7-8 people/adults aboard w/ full 29 gallons of fuel and cruised nicely.