1983 Merc Inline 6 115 at altitude

[cohobolo]

My 83 inline 6 is significantly bogging down at higher altitude. Is there an adjustment that can be done? I live at the coast and fish occasionally at higher altitudes (4-5000 ft), so it would be nice to be able to make an adjustment. Thx.

 

[Gomer50]

Re: 1983 Merc Inline 6 115 at altitude

I cant tell you what size because my chart only goes up tp 90hp in my book but for that elevation you might have to rejet your carbs to match the elevation.

 

[Chris1956]

Re: 1983 Merc Inline 6 115 at altitude

Standard jets are good for 0-5000 feet. If you are below that, no rejetting is necessary.

BTW only the high speed and backdraft jets are changed for altitude.

That motor only bogs at elevation?

 

[cohobolo]

Re: 1983 Merc Inline 6 115 at altitude

It runs fine at sea level. I live at the coast and use it in the bay and it really moves. But, when I take it up to one of the lakes I fish (4800'), it really bogs down. It sounds like it want's to go when you first take off, but then just can't get going.

 

[Coloradolakeboy]

Re: 1983 Merc Inline 6 115 at altitude

I would try a 2" smaller prop. That will help with the bogging. It helped me at 5000 ft. It's also easier to change props than jets.

 

[cohobolo]

Re: 1983 Merc Inline 6 115 at altitude

Unfortunately, it's a jet pump. If I could make some kind of adjustment short of replacing the jets, I could live with some power loss. The 115 is plenty of power for my flat bottom boat, but at this point it bogs down so much I can't even get on plane.

 

[Coloradolakeboy]

Re: 1983 Merc Inline 6 115 at altitude

Do you have an idle adjustment screw on each carb instead of jets? If so, that's the ticket.

 

[cohobolo]

Re: 1983 Merc Inline 6 115 at altitude

Do you have an idle adjustment screw on each carb instead of jets? If so, that's the ticket.

It does have adjustment screws on each carb. They are set 1 1/2 turn CCW from lightly seated. Any recommendations on how I should adjust them?

 

[Coloradolakeboy]

Re: 1983 Merc Inline 6 115 at altitude

I have jets on my 175, but do a search here. I believe it's CharlieB that has written some great stuff on the adjustments you need.