Prop Suggestions for Yamaha 90?

[cemiii]

Bob, thanks again, I never really had 3 motors on there, just hung the old tiny 2 stroke 15 to show the wild comparative size difference compared to the new 4 stroke 10.

The big plate on the back of the boat covers all the way down to the drain plug. It's hard to see because it's painted to match the bottom gel color. There is an 6x14 backer under the splaswell. I hit a rockpile at Eagle lake at 20 mph. I didn't want to look back for fear there was likely no transom or motors or at least prop left.

But I can see no damage except for the big blems on the Skeggard and a minor prop scratch. I was fortunate to have a skeggard on. But, it looks like the transom is fairly strong, via unintentional stress testing.

I don't have trim tabs and don't feel I really need them right now. I get great up down trim from the permatrim, and usually a half step move by a passenger or my self levels her laterally. As mentioned, she plains instantly without tabs. Sits fine in the water, pretty much parallel to the bottom gel coat line, even with full tanks and a 6 gal kicker tank.

It looks like a Mercury Black Diamond aluminum prop can be had in 16x11p and looks like it may take an XHS100 etec hub kit. Trying to confirm this. Another $150 experiment. I have a brand new power tech prop now but it's 15P and the lowest fitting pitch prop in their catalog.

Really sorry I hijacked Matt's thread. I hope he's gotten his answer. I think he has, but if anyone has anything else on yami-propping
please jump back in here.

I bought the motor used from a dealer out of FL who put it on a guys pontoon boat for about 20 hours and he forced the dealer to swap it for a short shaft motor. Now I know why, he probably couldn't prop it right either.

Chris

[Tortuga]

[thataway]

I noted the difference in the size of the motors--very dramatic! I figured that you had the bracing well covered from what I could see on the jack plate.

The difference between the trim tabs and the Permatrim is that side to side trim can be altered, and I have always brought the boat up to a level ride, than brought the outboard/I/O leg so it was pushing straight ahead--of course the Permatrim can alter all of this dynamic. You are correct, that the C Dory does not really need trim tabs, and I didn't have them on my 22, but they certainly do make a large difference without the Permatrim. (I have both on my 25--and adding the Permatrim made a definate difference, with more stern lift.).

My impression in talking with the Power Tech folks was that they could come up with props other than what were in the catalogue. When you go to a 16" prop, it will drop the RPM several hundred RPM--and the 11" will increase it several hundred--hard to know what the net effect will be, but it should be a lot of torque start up--not something which you seem to need. Bottom line, if you are runing at several different elevations; several different prop pitches will pay off. We had 17", 15" and 13" for the 90 on our 22--