Am I propped up right?

[crownlyfe]

Stainless Steel quicksilver mirage prop 23P, reaches around ~44-46 MPH with 3-4 people and some gear on the boat like cooler,beach chairs,tube,lifejackets etc.
5.7L alpha 1 on a 3100lb dry weight boat. For some reason I feel like I should be able to hit maybe 50?

 

[Maclin]

What RPM at top speed? Is speed by GPS or speedo? What size and type of boat?

 

[crownlyfe]

What RPM at top speed? Is speed by GPS or speedo? What size and type of boat?

Shoot forgot to check RPM some where in the 4000 range id have to go out and check again, 96 crownline 202 BR, speddo

 

[Chris1956]

50MPH takes a whole lot of power, and production boats are generally powered to hit 40-45MPH, at most. Check your GPS speed and report back on RPM, as well. I will be surprised (but not shocked) if you get to 50MPH with that powerplant.

 

[Faztbullet]

Carb, EFI or MPI??? The same boat with the 350EFI and the large Bravo outdrive will run 50+mph. Try tapping the trailer button at WOT to raise the drive as it may not be getting full trim.

 

[crownlyfe]

it's carb engine just went out to test 4050 Rpm 45mph is Throttle all the way down 4 ppl some gear full tank of gas, 32-35 mph around 3100 rpm, decent prop or should I look into something else

 

[Faztbullet]

21 pitch 4 blade will help..did you try try tapping the trailer button?

 

[Guest]

You should first start by determining what your engines WOT operating RPM is.
You have a 5.7 GM V-8 that whose WOT range is between 4500 to 4800 RPM. (confirm what yours is exactly with a Merc dealer)
The propeller you consider should not exceed the maximum rpm range at WOT.
If you're only turning 4000rpm, you need to drop the pitch to get the revs up.
As a general rule - a 2 inch reduction in pitch will increase the RPMs by 200
Good Luck