trim question

[fatrap]

My 150 Optimax is running a 21 inch Tempest. Last summer I had to have it rebuilt. I used to trim all the way up and got max speed with it that way. Didn't need to screw with it. All the way up its as fast it goes.... Now trimmed up as far as it goes the boat runs about 5mph less than before it was rebuilt with slight increase in rpm. I trim back down until the speed start to drop then raise and lower the trim very slowy. the prop seems to catch, the engine noise drops and the boat speed jumps about 5mph then I can go to max throttle and recieve my normal top in. Any idea? Send back for a re-do on the prop.



fatrap

 

[Bob Bourget2]

That sounds VERY typical for a "hack" rebuild. Chances are, if you look at the trailing edge of the prop, the rebuilder buffed off the "cup". It should be very sharp, from the hub to the "rake line", which is the part of the cup that kind of goes "around" the tip of the blade. If this sharp edge is gone.....expect less lift, increased rpm, and lost mph.....:blink:

 

[fatrap]

Thanks Bob.

what would you suggest? Just live with it?

fatrap