Yamaha 30 2stroke fuel/air

[Davidwd]

Hi all,
I have a Yamaha built 30 mariner, 2 stroke with oil injection. It is running rich, you don’t need any choke to start it from cold and the plugs are black.

Could anyone tell me the procedure for setting the mixture please and which screw it is.

Many thanks
David

[beamishken]

Originally Posted by Davidwd

Hi all,

I have a Yamaha built 30 mariner, 2 stroke with oil injection. It is running rich, you don’t need any choke to start it from cold and the plugs are black.



Could anyone tell me the procedure for setting the mixture please and which screw it is.



Many thanks

David

Are you sure the manual override isnt actuated into the permanently on position? That would put the choke on all the time. Or a failed fuel pump diaphragm will pour raw fuel into the crank case. Maybe do some checks first.
The mixture screws are in the side of the carb usually a stainles screw with flat screwdriver slot & a spring around the screw. Turn it in untill lightly seated then out 1.5 turns & your not far away. It realy only affects the idle mixture, has little effect higher up the rpm range as the carbs are fixed jets

Sent from my SM-G950F using RIB Net mobile app

[Davidwd]

Originally Posted by beamishken

Are you sure the manual override isnt actuated into the permanently on position? That would put the choke on all the time. Or a failed fuel pump diaphragm will pour raw fuel into the crank case. Maybe do some checks first.
The mixture screws are in the side of the carb usually a stainles screw with flat screwdriver slot & a spring around the screw. Turn it in untill lightly seated then out 1.5 turns & your not far away. It realy only affects the idle mixture, has little effect higher up the rpm range as the carbs are fixed jets

Sent from my SM-G950F using RIB Net mobile app

Thank you for your kind advice, I set the mixture as per your recommendations and it now runs perfectly.

D