|
If you prop for 4600 you will expoerience the best cruise speeds the boat has to offer. If you prop for 5000 RPM at WAOT then you should experience the top end. The power band of your motor is 4600-5000. If you fall below 4600 then you would be lugging the motor, consuming a lot of fuel and taking life off of your motor. So if you were to go to a 21P then you would loose 400 RPM putting you at 4200 RPM which is NO GOOD! So to answer your quetion you should not go to a 21P Mirage Plus as you don't want to fall below the 4600 RPM at WOT.
Julie |
Originally Posted by prosno
(Post 2149715)
Well Dave unless somethings wrong with gps or tach thats what I have, 4,500 - 4,600 rpms and grs says 40.
I know nothing about this model boat so I dont even know what its capable of. I'm not looking for total top end cause I'll be pulling my kid on a tube at times and cruising around the rest of the time. But in my opinion 40 at that many rpms is not good for all around. 40 knots = 46 MPH. And congrats on getting back in the game, maybe we'll see you on the river, happy boating |
Originally Posted by fredefox
(Post 2150511)
Better double check your engine. In 1987 Merc called the 7.4 (300 prop shaft hp) a Mag. It was not the 365hp mag, if the boat came with an alph drive. RPM for the engine is 4200 to 4600. 23 foot Boat and 300hp will not pull a 21 pitch. 17 stainless mirage plus likely to be good beginning point.
300HP at the prop, 1.3 Alpha drive. The boat should top out at 50mph. |
okay I checked a few things today, engine is 454 330 hp, outdrive is geared 1.47 and is a rebuilt lower unit. Going to mess with it this week end I hope and write down all results. Thanks a bunch guys, Dave I hope to see ya on the river, gotta post some pics of this thing soon.
|
Originally Posted by prosno
(Post 2152324)
okay I checked a few things today, engine is 454 330 hp, outdrive is geared 1.47 and is a rebuilt lower unit. Going to mess with it this week end I hope and write down all results. Thanks a bunch guys, Dave I hope to see ya on the river, gotta post some pics of this thing soon.
See you on the River...:drink: |
| All times are GMT -5. The time now is 09:32 AM. |
Copyright © 2026 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.