High Altitude prop question.

S.D.Brian

Recruit
Joined
Sep 9, 2024
Messages
1
Hey Everyone,
I have a 1988 17’ galaxy open bow fish and ski boat with an inboard 2.5li Mercruiser alpha/gen 1.
My question is- I live in San Diego, and I take her out to the local lakes. But I also go up to the sierras to do a lot of fishing. I want to start taking the boat but don’t want to re jet the carb every time I go. Can I just swap out my current prop for a High Altitude prop?If so any recommendations( $150 is my max I’d like to spend) I’m only up there for a week at a time so re jetting each time I go sounds like to much.
Any and all recommendations are appreciated.
Tight lines.🤙🏻

Brian.
 

jimmbo

Supreme Mariner
Joined
May 24, 2004
Messages
13,457
How much higher in Altitude? What is you WOT Rpm at you usual Location? And what is the WOT Range of the Engine.
 

froggy1150

Master Chief Petty Officer
Joined
Nov 3, 2017
Messages
846
Remember it's about the air. With less available o2 per volume of air because it's less compact your air/fuel ratio will be off.the only way to truly correct this is to adjust fueling.
 

froggy1150

Master Chief Petty Officer
Joined
Nov 3, 2017
Messages
846
Altitudes

For small changes in altitude, carburetors will compensate without any modifications. For larger altitude changes, carburetor jetting adjustments may be needed. A rough estimate is one to two jet size reduction for every 1,000-foot elevation increase.
 
Top