different jets for elevation change

G

gfoutt

Cadet
Joined
Apr 6, 2011
Messages
6
anyone know what jets i should use in my 88 2 stroke 60 hp mercury. the guy i got the boat from lived right around sea level and i'm at 5800 feet. s/n 0b343914. im new to 2 stroke outboards and trying to figure out if the jets will effect it bogging out at higher rpm. Thanks in advance.
 
achris

achris

More fish than mountain goat
Joined
May 19, 2004
Messages
27,468
Re: different jets for elevation change

In the most part the best solution to operating at high altitude (as recommended by Merc) is to reduce the propeller pitch (fit a different prop) to allow the engine to get up into the recommended WOT range.

If there is still a problem, then changing jets becomes the only other option. But try a different prop first.
 
G

gfoutt

Cadet
Joined
Apr 6, 2011
Messages
6
Re: different jets for elevation change

ok thanks i'll try and figure out what i have and what i need. I appreciate it. what does WOT mean?
 
j_martin

j_martin

Admiral
Joined
Sep 22, 2006
Messages
7,474
Re: different jets for elevation change

WOT is Wide Open Throttle

If you look in the maintenance manual for that engine, there'll be a jetting chart. You should jet it leaner at that altitude. Some jets increase in size to do that, and some decrease. It depends on the application. The charts will specify exactly how much which way.

The engine will still run at reduced power, just because it can't get as much of a fuel/air charge in the cylinder. That's why reducing the pitch on the prop is also usually required.

hope it helps
John
 
achris

achris

More fish than mountain goat
Joined
May 19, 2004
Messages
27,468
Re: different jets for elevation change

A few years back Merc changed their recommendations for high altitude. They no longer recommend jet changes. Just change the prop to get back to the recommended revs at full throttle. I suspect people were changing jets (to a leaner main in particular) and returning to 'sea level' and forgetting to change back to a richer main, then ending up popping pistons...

Cheers,

Chris.......
 
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