Hi all. I have a super little 1988 Evinrude 48 SPL that has been doing great for several years here in Texas (elevation 400 ft.). I will be heading up to Idaho for some fishing on lakes 4000-5000 feet elevation. My carbs have a low speed and a high speed fixed jet. Currently, the high speed jet is stock size 50D and the low speed orifices are 32's (I found it runs better with 32's than the stock 36's).
My question is what jets should I go to for the higher elevation? Previous posts suggest decreasing the high speed jets .001 per 2000 feet and increasing the low speed orifices by the same increment. Plan is to go to 48D's and 34's respectively. I just want to check that this is proper. The low speed orifice (#9 on the diagram) is an air bleed, so increasing the size results in a leaner mixture, right?
Also, if I change the high-speed jet will that effect the idle mixture in any way even without changing the idle orifice? Some posts I read seem to say that changing just the high speed jets changes both the high and idle mixture even if you leave the idle orifices alone.
Thanks for any advice. This forum is awesome!
P.S. I don't plan to re-prop because my boat will be lightly loaded and has plenty of power already so I'm not too worried about power loss, holeshot, etc, just want to get the mixture right.
My question is what jets should I go to for the higher elevation? Previous posts suggest decreasing the high speed jets .001 per 2000 feet and increasing the low speed orifices by the same increment. Plan is to go to 48D's and 34's respectively. I just want to check that this is proper. The low speed orifice (#9 on the diagram) is an air bleed, so increasing the size results in a leaner mixture, right?
Also, if I change the high-speed jet will that effect the idle mixture in any way even without changing the idle orifice? Some posts I read seem to say that changing just the high speed jets changes both the high and idle mixture even if you leave the idle orifices alone.
Thanks for any advice. This forum is awesome!
P.S. I don't plan to re-prop because my boat will be lightly loaded and has plenty of power already so I'm not too worried about power loss, holeshot, etc, just want to get the mixture right.
