40 Mercury Help

[Snoopybase]

I think it is a 94 model but not sure <br />anyway It dies out in midrange and idle.<br />I can bump the choke when it starts to die out and it will pick back up again. It run ok at full throtle. I have cleaned the carbs twice checked the fuel lines etc.<br /> Help???

 

[bob58]

Re: 40 Mercury Help

Try turning fuel/air mixture jets counter-clockwise 1/4 to 1/2 turn each and see if this richens up the fuel mixture and helps your problem

 

[Snoopybase]

Re: 40 Mercury Help

Thanks Still_Learning<br />I opened them up a half turn each.It runs good in the driveway but you know how that is. It will be next weekend before I can put it in the lake.<br />I had already opened them up one half turn this makes them open at 2 1/2 turns each does this mean there could be another problem?<br /> Thanks

 

[Elmer Fudge]

Re: 40 Mercury Help

Two and a quarter to two and half turns sounds about right,check your plugs and see if they're dry or moist,also do a compression test while you're at it.

 

[bob58]

Re: 40 Mercury Help

What I do with mine is set the jets in gear at a an idle while tied to the dock. If it stays running there it is close enough to go out and have fun. If I set them to the best idle in the driveway the engine is too lean on the water and dies. Turn them out until the motor RPM's slow down then turn in clockwise slowly until the RPM's start to slow the other way and try a point in the middle.

 

[Snoopybase]

Re: 40 Mercury Help

Thanks for the Info.<br />What should the compression range be ?<br />If the plugs are wet or dry which way should I turn the air mixture ?<br />Should I try to turn them both at the same time?<br />Give me one carb at a time I'm ok but two aughhh.<br />Thanks ya'll have already been a big help.

 

[Elmer Fudge]

Re: 40 Mercury Help

If plugs are fouled you're too rich,if they're dry and burnt looking you're too lean,and if they're lightly fuel coated or moist that should be about right,adjust them the way Still Learning said,that's pretty much how i did mine.On the compression test psi should be within a 10% variance per cylinder.