Yamaha Prop Size

[live_baiter]

hi all,

would a 15inch and 19 pitch prop suit a 150hp counter rotation yammy engine?

LB

[Geoff]

I'm running 15" on a Yammie 70hp so would think for 150hp something larger would be required

Geoff

[a boat]

Hi, I think he means 15 inch diameter x 19 inch pitch and pitch is the important factor in determining revs. IF the splines are to suit a Yamaha and the prop is a LH rotating one than it could fit on your engine and work, but the WOT RPM might not be right. You want to see about 5500 with your normal load at WOT.

Cheers,

Huey.

[live_baiter]

hi Huey,

i have a 21inch pitch on it at the moment and can only get 4500RPM....

thats why i want to go smaller pitch.

[a boat]

Hi Mate, if engine is running as designed that is you are reaching full throttle, the syunc and link is right anmd the timing is good then you will need to drop more than a couple of inches to get the 1000 odd revs you need. Confirm engine height is correct first and the AV plate should be above the water when trimmed correctly and also trimming out at WOT can add revs. If all is right with the engine and set-up i think look for a 15 or 17 inch prop, but if you are a counter rotating engine it will be hard to find one second hand. Do you have a counter rotataing engine?

Cheers,

Huey.

[live_baiter]

Hi Huey,

yeah it is a counter rotation motor.

[a boat]

Hi, then it will work, but as mentioned I do not think it will be the right pitch to get to your ideal revs at WOT.

Cheers,

Huey.