Low Speed Stalling

[Eric2]

I have a 1999 Yamaha 9.9HP electric start outboard. At low speed it will sometimes stall, usually at a critical moment like docking. It runs like a top at any other speed. The idle speed is normal. At low speed It apears to suddenly lose fuel pressure, if I pump the primer it will always start again. Can you help?

[wob]

Sounds like your carbs are dirty. Trying running some SeaFoam through your gas and see if that helps any.

[Hamfisted]

On carbed engines the idle jets will get clogged up with gum and varnish if the engine is not run routinely. When fuel is allowed to evaporate in the carbs it leaves a residue behind that builds up in the bottom of the carb bowls and particularly the idle jets. Go to www.YamahaPubs.com and order a service manual for your motor. It will have detailed information on cleaning out the carbs. Your main concern is the idle jet.
As posted above, try some Sea Foam (Advance Autoparts) in the gas as a routine maintenance item. You can also run some Berryman's Chemtool (Walmart) through the gas tank and see if that'll clear it up, that stuff is pretty strong.


Mike