2003 8hp Merc...trying to find high altitude jets

aaarneson

Petty Officer 2nd Class
Joined
Mar 4, 2009
Messages
116
Trying to find the correct jets for 6000 to 8000 elevation.

Ran at about that elevation this weekend and hardly any power compared to 1500-2000 elevation that runs at about 18mph.

SN: OT618494
 

aaarneson

Petty Officer 2nd Class
Joined
Mar 4, 2009
Messages
116
Also I have a 3 blade prop and a 4 blade. The 4 was in at this high altitude....would the 3 blade be better?
 

Fun Times

Moderator
Staff member
Joined
May 16, 2009
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8,826
Trying to find the correct jets for 6000 to 8000 elevation.

Ran at about that elevation this weekend and hardly any power compared to 1500-2000 elevation that runs at about 18mph.

SN: OT618494
You generally tend to find the altitude info inside a service manual for your engine model…, Here would be the part number you’d need… Maybe try searching the part number online to see if there’s a copy online already. https://www.mercruiserparts.com/827242r02-sm-o-b-6-15-2s

 

roscoe

Supreme Mariner
Joined
Oct 30, 2002
Messages
21,667
3 blade or 4 blade means nothing without knowing the pitch of each.

any mercury dealer should have them.

The correct jet will balance the air/fuel mixture, and aid in running, but you will still experience a loss of power due to the air up there.

probably loose 1/2 of your power at 8000.
a properly jetted 15 hp is what you need.
 

jimmbo

Supreme Mariner
Joined
May 24, 2004
Messages
12,989
Jets are not an item most dealers keep in stock(unlike spark plugs, they rarely need changing). If available, they can order them
 

airshot

Rear Admiral
Joined
Jul 22, 2008
Messages
4,380
Also I have a 3 blade prop and a 4 blade. The 4 was in at this high altitude....would the 3 blade be better?
Usuall they drop a couple inches of pitch when they move to a 4 blade prop, check yours...if same pitch or higher than the 3 blade, then you hurt your power output.
 
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