Welcome Guest - Sign Up today
Welcome Guest - Sign Up today


No announcement yet.

Yamaha 9.9, Carb and fuel clean, Idle screw fully screwed in, won't idle

  • Filter
  • Time
  • Show
Clear All
new posts

  • Yamaha 9.9, Carb and fuel clean, Idle screw fully screwed in, won't idle

    I've just cleaned the carb on my yamaha 9.9 four stroke. Previously, it ran fine with throttle open but would idle very poorly and died when throttle opened or shifted into gear.

    Cleaned the carb, found the choke and butterflies (throttle and choke) gummed up with brown stuff. Also a fair amount of brown dirt in the bowl and some holes blocked. Dismantled both butterflies and cleaned them and choke tubes, and cleaned carbs and all jets and fuel holes.
    Pumped a pint of fuel into a bowl prior to connecting the carb and fuel clean.
    It now runs a lot better, but idles barely. It shifts into gear OK now, and also responds to opening the throttle wide from Idle. However, I'm pretty sure its idling too slowly since it's very lumpy and dies after a short time (Don't have a tacho). The idle screw is turned fully in against the spring.
    Is something worn? The engines are 10 years old.
    Is there a mixture screw somewhere?
    Is it possible the timing has gone off after 10 years (although it runs great with throttle open).
    Any other thoughts?
    Thanks in advance
    Ron James

  • #2
    Sign up today
    If there's a mixture screw somewhere probably is way off. If no one has fingered the timing, before leave it there..

    Happy Boating

    Sea Rider 320, 380 Sibs, 450 Rib, 2 Strokes Tohatsu 5,18 & 30 HP Proud Smokers