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#1 Wed, Feb 24, 2010 1:07 PM

From: Summerfield, FL
Registered: Tue, Nov 24, 2009
Posts: 41
Skis At: Lake Weir and Blue Lake, Ocala,FL
Foot Forward: Right

Motors and RPM's

Ok, so this winter we replaced the motor in out 96' Malibu Sunsetter. We dropped in a new Indmar 320. I have been putting some go break in hrs on it so far with some free skiing and a little trick'n and bringing it full bore a couple times real quick to see what se has since we do like foot'n as well. So any how to my question. I am pinning out at 45 mph but only 4550 RPM's. Through the years I have always heard the numbers 4800-5000. Should I reprop to get there or being that I am getting the speed I want at a lower RPM is that ok? Just lookng for some input. I thoughts are I am saveong gas and getting the spped I want. If it was way off then maybe I see a problem. But?

"It is what it is"



#2 Wed, Feb 24, 2010 1:19 PM

From: New Hampshire
Registered: Mon, Jul 27, 2009
Posts: 83
Foot Forward: RFF

Re: Motors and RPM's

You might want to throw that question on themalibucrew.com   I'm sure you'll get tons of feedback.  Peeps there are always willing to help you spend your $$ (wisely).

You may want to drop an email to the guys at acme marine.  I'm sure they would be able to direct you to their appropriate  prop for maximum benefit.



#3 Wed, Feb 24, 2010 3:07 PM

Slalom Mentor
From: Cypress, Tx
Registered: Sun, Jun 1, 2008
Posts: 337

Re: Motors and RPM's

You want the prop to match the torque curve of the engine. Since that is an OEM engine for some malibu's there should be some data on props. It's quite possible that when that engine was put in a boat, it used a different prop than the standard engine. Everything is a trade off. What you run the risk of, is putting the engine in a different part of it's torque curve with which could lead to a softer or more harsh ski pull.

Shane Hill



#4 Thu, Feb 25, 2010 4:48 AM

From: Redwood City CA
Registered: Mon, Dec 8, 2008
Posts: 21
Skis At: Sacramento Delta
Foot Forward: right

Re: Motors and RPM's

The specs that come with the engine should give the full throttle rpm every engine may be different. If your boat is proped properly then full throttle should fall within this range. Most prop companies will do a analysis for you. That said when I put a new engine in my boat I switched to a 4 blade prop and the wake was better and the boat ran much smother.
There are so many choices it will make your head spin.




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