Re: Yamaha 90 prop??????
Think you might be goin in the wrong direction. You need to find out the max WOT recommended for your engine (I don't know your 90 but would suspect it would be around 5000 rpm). Then pitch the prop to match this rpm. You drop pitch to bring rpm up and add pitch to bring it down. So the 19" is the wrong way to go from a 17". Might need to go to a 15" instead. That should bring you to around 5-5100 rpm. Your hole shot should improve and possibly top end as well as the motor will be performing at it's peak power rather than trying to slug it out.<br /><br />You don't always need to buy a new prop. Most "good" prop shops can tweak the prop you have (change pitch and add a cup to the blades). Compare the cost with a new prop and decide according to you wallet.
