90 hp yahama coughs at idle

[old wise bison]

Engine runs perfect at all ranges accept idle ,then it coughs and sometimes dies -- spark or fuel??

 

[robert graham]

Assuming? this is a 2 stroke motor maybe remove idle mixture screws/jets (remember number of turns out from lightly seated each one), then spray some carb cleaner into each orifice followed by a shot with air hose to clear circuits....replace/reset screws/jets.....this might help cure a lean condition at idle. The mixture screws/jets are on top of each carb.

 

[Mohawkmtrs]

Most likely fuel

 

[QBhoy]

Easy try would be a good strong dose of seafoam. Less easy would be a carb clean. Probably more likely caused by a bad diagram pump ?

 

[Doh]

Idle Screws out 1/4 of a turn each. Cold Blooded Engines 3 Banger Yamahas.