OMC Propeller

Lsnow

Cadet
Joined
Feb 28, 2012
Messages
22
I have a 1985 boat with a 3.8 OMC I/O. I live at an elevation of about 4500 feet. At this elevation, my boat maxes out at about 32 mph. I went to a lake two weeks ago at an elevation of 7600 feet. My boat maxed out at about 26 mph. The prop on my boat now is a 15 x 17. I'm considering a different prop for the higher elevation lakes. What prop pitch should I consider? Or what else an I do to get my boat to run better at the higher elevation lakes?

Thanks.
 

Lsnow

Cadet
Joined
Feb 28, 2012
Messages
22
Re: OMC Propeller

I don't know what the wot rpm was. I will pay attention to the on the lake tomorrow.
 

steelespike

Supreme Mariner
Joined
Apr 26, 2002
Messages
19,069
Re: OMC Propeller

If you boat pretty much exclusively at 4500 or mopre you could jet the carb for the 4500.woul;d work well at 4500 and improve 7600.
If you jet for 7600 it will be too lean for lower elevations.
The idea is to jet the motor and select props so the motor can run within its max wot rated rpm range.
probably 3800 to 4200 rpm.
 

Lsnow

Cadet
Joined
Feb 28, 2012
Messages
22
Re: OMC Propeller

Today at a lake at 5400 feet, wot rpm was 4100 rpm.
 
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