Anyone know how to determine what pitch size I would need for a 2004 Crownline 202LPX Boat w/ 350 Mag Alpha 1?

Question

I currently have a stock black aluminum 19 pitch prop and am wanting to upgrade to a stainless steel and what brands do you recommend?

Answer 1

There is only one way to determine the proper prop and that is first decide what you want to use your boat for,skiing,fishing,cruising.

Once you have done that check with your dealer to get the suggested prop,and to check the max RPM for that engine.

  Take the boat out rigged as you would for the type of boating that you have decided on,and try it.As a rule of thumb a change of 1" of pitch will change the RPM's by 200.That is if you go up 1" then the RPM's will drop by 200, and reduce pitch too increase RPM's.

  Now ideally you want to have the max RPM's at WOT 200 RPM's below max RPM of the engines rating.

Also when you change from alum.to stainless you drop 1" of pitch,this is because stainless does not flex under load.

I hope these tips help in your decisions.

35 years as a marine tec.

Answer 2

Check with a Mercruiser dealer, they will have the specs and the stainless steel prop for your boat. Also you need to determine what you want your boat to do, like sking ,cruising and such! A 21` pitch is good out of the hole for skiing but you will lose top end speed, probaly 5 to 7 mph, I `m not positive but you may lose or gain  rpms.