2002 Honda 9.9 4 stroke runs rough when past midway on throttle

[Over bored]

This engine starts fine, idles well, accelerates o.k. until the throttle is turned past the mid-way point. Then it smokes, acts cranky and rough until the throttle is decreased.
It's been sitting for a couple of years, but I cleaned out the fuel tank, put in Sea Foam and new fuel, pulled the fuel line off at the engine and squished all the old fuel out of the line so none would get in the engine.
Haven't put in the water yet; just using the hose and the water muff.
Any ideas and suggestions would be appreciated.
Thanks.

 

[hondadude]

Open the drain of the carburetor and flush out the carburetor with your fresh fuel..

It is possible that nothing is wrong. Most engines need the back pressure of the water for them to run at high speed.

It is also possible that the carburetor needs some work, but you will not know for sure until you put the engine under load in the water.

You can check the throttle up situation with your boat just backed into the water. If it coughs and sputters, don't bother taking it out on the water. Check spark plugs, and compression. If ok, then get the carburetor cleaned.

Also make sure your oil level is about 1/4" below the full mark. Too much oil will make this motor bogg down.

You should also check all the vent/breather hoses for critters. If it was sitting for two years, who knows what kind of critter built a nest or two in the hoses.

Mike



Mike

Mike