low idle

New to the forum.

I have a 1991 yamaha 200 hp, recently running rough and stalling at idle and when first put in gear. A new set of plugs seemed to help initially, but now it stalls again when in idle or just into gear, and is very diff to start.

The RPM's seem to be running in the 300-400 range when trying to idle.

Could the problem be as simple as the idle set too low? or is it more liley the carb / fuel lines. Does anyone know where the idle speed adjust screw would be on this engine?

Thanks for any help.

[jb123]

start with an auxillary tank to rule out a tankside issue. while running on the hose at say 12oo rpms, pull each plug wire at a time, listening for a non firing cylinder/ and decrease in rpms. then you can pull the airbox and choke each throat with your finger, again listening for increase in rpms.
most likely dirty carbs, doing these will point to the dirty ones.