Low Speed Mixture Screw

[Tido25]

hey i took my boat out today and it ran great but idled really bad the manual says the low speed idle screw should be set like this----Turn low speed mixture screw slowly inward (clockwise) until it seats lightly, then back
screw out (counterclockwise) 1?1/2 to 1?3/8 turns(turning mixture screw in tight will
damage needle and seat). mine was at 3 - 1/2 full turns whould this make my motor not want to idle but run great? the motor is a 1983 mercury 25 6348410 thanks guys

 

[FLATHEAD MAC]

Re: Low Speed Mixture Screw

Set it to the manual. Suonds as if getting toooo much fuel at idle. But using the extra fuel when on the run, mixture screw might has some how backed out to the 3 1/2 turns

 

[Tido25]

Re: Low Speed Mixture Screw

Hey thanks for the fast reply I put it to spec and I'm going to change the plugs in the morning and try to find some of that power tune or what ever it's called that mercury sells to spay in to the carb hopefully it helps

 

[Rat-Ripper]

Re: Low Speed Mixture Screw

If your motor seems to run fine at higher speeds but stumbles and runs rough at idle or trolling speeds you are probably running too rich ....This is easy to check ..the spark plugs will build up oil at trolling and begin to stutter and possibly stall and then if you take it for a quick run , the plugs will clean up again but then when you try trolling they will build up oil after 10 to 15 minutes and stumble again and possibly stall .. This was happening to my 2008 50 Merc 2 stroke . I turned the idle mixture screws from the factory 1 1/4 to about 1 1/8 and this solved the problem ....
If the motor hesitates on throttle then you are too lean ..slightly turn idle mixture screw out .
Your idle rpm should be set to around 675 rpm ....if it is too fast , it will be too hard on your motor when you shift into gear . I hope this is some help ...

 

[Tido25]

Re: Low Speed Mixture Screw

Well I had it tuned and running great but now it's on the bottom about 30 ft under water so thanks for all yalls help but it's gone now

 

[treker]

Re: Low Speed Mixture Screw

That sucks, what happened?