MacGregorSailors.com

Hello - a fellow 26M owner on my lake has a question about what size and pitch of a propeller he should be using on his 70 hp Yamaha. With his current propeller, he can't get to 24 mph with the ballast out (which from previous reading on the forum he should be able to obtain). His motor tops out at 5300 rpm. Thanks for any help you can provide!

Edit: it is a 4-stroke, and he thinks it is rated somewhere in the low 6000 rpm range... though a quick google search implies 5800 rpm on one page, or a range of 5300 - 6300 on another page (I guess depending on load)...

We have a honda 60 bfp which has a 70hp foot. It is a 15 spline prop and the smallest they make for it is a 14 inch X 9 pitch. which when empty will drive the boat about 20 mph at 5200 rpm. Ours is 4 stroke. So folks need to know if it is a 4 stroke or 2 stroke. Also what is the rpm range for the motor as a honda 60 is 5000 to 6000 rpms.

I have the 70 Yamaha on an X, not an M, so there may be some slightly different results. I have 2 props. Right now I have the Michigan 101036 which is a 14" 11 pitch 3-blade. Light to medium loads works great. If I was to always be on the heavy side of loads, I would put my other prop on, the Michigan 101031 prop which is a 13-5/8" 13 pitch.

mallardjusted wrote:I have the 70 Yamaha on an X, not an M, so there may be some slightly different results. I have 2 props. Right now I have the Michigan 101036 which is a 14" 11 pitch 3-blade. Light to medium loads works great. If I was to always be on the heavy side of loads, I would put my other prop on, the Michigan 101031 prop which is a 13-5/8" 13 pitch.

My 75 is the oposite

I have a 14x11 14x13 13.75x15

I find the heavier I am loaded, the lower the pitch I need

Heavy loaded for long trips, 14x11
Great Hole shot

Light load, 13.75x15
Great fuel eco and low rpm cruise

Cheers

G