? about the right prop for elevation change

[Derric]

I have a 84 Mercury 2 stroke outboard 90hp with 17pitch prop on it. I like to fish the higher lakes 5000 ft and above would I need to go up to a 19 or down to a 15 to get max performance at that elevation?

 

[Barnacle_Bill]

Re: ? about the right prop for elevation change

You need to re-jet the carbs for that elevation. If I knew what carbs you have I could look it up for you.

 

[Derric]

Re: ? about the right prop for elevation change

Mine is a L6 1979-86 90hp. Do I have to change just the main jet or the vent also? My book shows a .070 for the main and .094 for the vent. My serial number starts with 5671804 I think I know first 3 numbers are right. Thanks for the help. I like getting in and doing things myself as long as I dont have to tear down the motor Ya know?

 

[Barnacle_Bill]

Re: ? about the right prop for elevation change

Yes, you need to change both.