1997 YAMAHA 40 HP OUTBOARD (LEAN SNEEZE THEN COUGH?) TROUBLESHOOTING STEPS

[tcarpe1]

Any idea of troubleshooting steps I can take to resolve the lean sneeze and/or cough issue I have will idling?

 

[ondarvr]

Clean the carbs and then adjust the low speed screws (if it has them).

You could just adjust the low speed screws, but if it ran correctly before it normally means the carbs are dirty now.

 

[tcarpe1]

Could it be a gasket?

I can handle the carb cleaning.

 

[ondarvr]

Could it be a gasket?

Could it be...yes...it that the common cause...no. You will know when your remove the carbs to clean them.

 

[tcarpe1]

Alright. Probably get around to it Friday or Saturday and give it a shot.

 

[tcarpe1]

So I messed around with it this afternoon with it in a barrel. I adjusted the screws and the coughing went away, but I guess I'm a little confused. I thought that the more you screwed the screw in the lower the idle, but I swear I think it was doing the opposite. At one point I had fuel coming out of the middle carb (hole on side up top). So is it screw in for higher idle? I did not put in gear to see what the response was, but I will mess with it more tomorrow. Things are getting better

 

[99yam40]

When the carbs are clean you set the pilot screws to the specs in service manual if that does not run well then you need to do a better job of cleaning.

always follow the link and sync procedure after installing the carbs after cleaning on a multi carb motor.

only way for fuel to come out the vent is for the needle and seat is letting to much fuel into the bowl causing it to come out the vent.

as you lean out a 2 stroke it will run faster.
usually it will not run well when picking up load and may harm the motor