Merc outboard won't idle

[JewelledJester]

I have a merc 9.9 outboard that won't stay running without hitting the primer button on the carb. Has fresh gas and new plugs. Possible debris in carb? Any help would be nice, want to put in saturday.

[artbyjody]

Originally Posted by JewelledJester

I have a merc 9.9 outboard that won't stay running without hitting the primer button on the carb. Has fresh gas and new plugs. Possible debris in carb? Any help would be nice, want to put in saturday.

I found on mine that idling when it hasn't been run for a long time it would do the same (it was brand new btw). I ended up keeping in neutral and increasing throttle up halfway between idle and full boar, let it run like that for three to five minutes (primer turned off), then bring it back down into idle worked well.

[Omatako]

You possibly have some oil congealed in the idle circuit from prologed non-use.

Try running the engine at about half throttle then block the intake with your hand until the engine just about dies. Remove your hand in time to let the engine run up again. This will draw any cr@p in the idle circuit thru and clear the sinuses so to speak.

If this works, try running the engine dry when yu're done using it, that will stop oil blocking the jets once the fuel has evaporated off.

[timebandit]

I might try inducing a SEAFOAM mix via a seprarate fuel line and a small tank.

If that does not work, pull the carb and clean.

[docbob5707]

Had the same problem with my Mercury 9.9 Big Foot. Ended up rebuilding and cleaning out the little orfices in the carb. (Real simple job BTW).