Yamaha outboard

[MrChachi]

I have a 1996 Yamaha outboard 40 hp 2 stroke that won’t idle! Carbs are all clean jets are all clean I believe it’s the fuel mixture screw does any one have any suggestion, or know the screw turns?

 

[boscoe99]

1.5 turns out from being lightly seated.

 

[GA_Boater]

Welcome aboard.

After the initial 1.5 turns, the final adjustment is in the water, in gear. You can back the trailer down with the boat still tied down, start her up, put it in forward and idle and turn the screw in until the motor stumbles, then back out until it stumbles again. Count the turns and put the screw it the mid-point. Do the other carb the same way. You should be good to go.

 

[MrChachi]

GA_Boater what do you mean put in forward and idle

 

[GA_Boater]

What I said - Forward gear and idle the motor. Don't rev it up in gear, just let it idle.

 

[Sea Rider]

Is there a great difference adjusting mixture screw at neutral/idle and gear/idle ? Anyway adjust mixture screw when OB is sufficiently warmed up for an efficient carb adjustment. Re adjust idle rpm if needed after mixture adjustment for OB to gear smoothly and doesn't die due to being adjusted too low on revs.

Happy Boating