21P Mirage Copy/250 XS Merc

[RidgeRunner]

Ferm was perplexed as to why the MPH wasn't higher, he never actually said you need a new prop. The worked on 24p Tempest has a lot of propslip with the motor height and trimmed to the moon and vessel light I can still find the limiter. I have a plethora of props to use and try. The stock 23P Tempest hits the limiter but not as hard as the 21P. I think I will leave the 21 on there for a while. Acceleration is fun..

[THEFERMANATOR]

I'm wondering if you don't have a 2:1 lower unit ratio in it. I know I hit 53 with a 17 pitch MIRAGE copy on my HYDRA-SPORTS which was only about 3-4% prop slip. If your running even a stock 1.86:1 lower unit ratio, then your prop slip even on the 21 at 60 must be around 18% or so which is on the high side(5-8% is just about ideal at WOT, with 12-15% considered ideal in teh cruise range). if you had a 2:1 lower unit, that would explain your high RPM's with a 21 pitch prop. I know my flats boat with stock 1.86:1 lower unit hit 60 with a 21 pitch TROPHY plus, but I had it jacked up high and was still only turning 5600 with it slipping and blowing out all over the place.

[jasoncooperpcola]

Originally Posted by RidgeRunner

I think I will leave the 21 on there for a while. Acceleration is fun..

[RidgeRunner]

I know my propslip is still high. Not as bad as the Tempest.. They are 1.86:1 gears. I am not sure 2:1 was even available in the 3.0Liter Torquemaster. Did your Hydrasport have a T-top and a refrigerator of a console?

[THEFERMANATOR]

No t top, but it did have a big console in it not to mention teh hydra sport weighed a good 600 pounds more than a v-20 does(it was one HEAVY built 20 footer with ceramic, kevlar, and heavy wood construction). I'm just surprised your mirage type prop has that much slip. I was running a mirage type and only about 3% at WOT(53 MPH was 5600-5700 RPM's). And I thought some of the sportmasters were made with 2.1:1 for pushing heavy scarabs.