I have a 2000 40 HP 4 stroke on my pontoon boat<br />While running at higher RPM's and then decelerating back to idle (slowly or quickly) the engine stumbles and sometimes stalls. Also at the end of last year it was a bit more difficult to start. I run it at least once a week and use fresh gas and new spark plugs. It seems to stumble right about when the idle jets meet the higher speed jets. A mech. also told me it might be a cam inside the engine that is causing the problem. I've run Seafoam thru the gas, would power tune help. As I recall it did this ever so slighty when new but was very minor then, now it's a bigger deal. Any thoughts?!
