Outboards at altitude.

[marty_scher]

My new 40HP 2 stroke Johnson could hit about 20MPH and 5500 RPMs,at a lake at 6500 feet. <br /><br />A week later it would only hit 17.5 and 4800 RPMs at a different lake, which is 8500ft.<br /><br />Does this seem about normal?<br /><br />Is there a good way to deal whith these altitude changes without a lot of jet changes or other carb adjustments? <br /><br />Should I care?<br /><br />Thanks

 

[petryshyn]

Re: Outboards at altitude.

Change jets or....grin and bare it!<br />The higher you go, the richer the mixture....(I'd recommend to decarb more often)<br />Atleast it won't burn pistons....

 

[martyscher]

Re: Outboards at altitude.

Do the EFI outboards compensate for altitude?<br /><br />Thanks

 

[petryshyn]

Re: Outboards at altitude.

Thats a subjective question. Anyone that has a MAP sensor probably will. I know some of the newest do. Not sure what year and models except for the 200yamaha. I'll bet that they all will by 2006. They'll all use 02 sensors by then as well(even 2-stroke)