115 yamaha 4 stroke problem at low rpm

[iceman29488]

i have a 2006 115 four stroke on my pontoon. bought it new. It has 42 hrs on it. At 20 hrs i had it serviced. the prob. im having started about 2 weeks ago. I was back *****ing at idle for about 30 min. and when i went to take off the motor sounded like a 2 stroke loading up. after running it up the prob. went away. now when im at low rpm it runs smooth and then every once in a while it skips for a second then runs smooth then it skips once or twice When you throttle up it gets up to speed and planes no prob. It reaches 5600 on the tac and thats what it always ran. i checked and cleaned the water seperator filter and the filter bowl on the motor. All were clean with no water. Shop said there is a metal fuel canister with a drain on bottom that might have water in it but havent drained it yet. ANY IDEAS WOULD BE GREAT

GARY

[boats.net]

Might try a new set of spark plugs.