Elevation effects on Merc 115 EFI 4-stroke

Kevin and Gail

Recruit
Joined
Aug 26, 2001
Messages
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I have a 2001 Merc 115 4 stroke EFI outboard that is on a 19 ft Alumaweld. Purchased new last July, 2001 in Portland, OR. Max RPM is typically 5100. Went to Montana which is at least a couple thousand feet higher in elevation. The motor would not exceed 4300 rpm at WOT and was very sluggish as if it was choking out. This lasted throughout the trip. I assumed it was due to the higher elevation? On the other hand, I thought the Merc 115 was self adjusting on fuel/air ratio? When we returned to the lower elevation, the motor again ran fine at 5000 rpm. Anyone know about the self-adjusting asumption on this motor?
 
D

DJ

Guest
Re: Elevation effects on Merc 115 EFI 4-stroke

Kevin and Gail,<br /><br />The EFI system can indeed adjust the fuel mixture for conditions, however it cannot make up for the lack of oxygen. Less O2=less power.<br /><br />The only way to make up for the lack of oxygen is through turbo or supercharging.<br /><br />I also believe your engine may be turning a bit slow at WOT at 5000 rpm.
 
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