Don't touch your carbs until you know for sure its not something else. It sounds like carbon build up to me. Run the can of seafoam thru a tank, and see what happens first. Slow trolling on a 40hp two stroke causes a lot of build up, trust me I know. I do the same with my 40. Once you've run the can of seafoam thru it, add an ounce or two to each tank from then on. Its also a stabilizer, gas line antifreeze, and fuel system cleaner. It will help, I guarantee it.
Don't mess with your jets until you've tried it, you could cause more serious problems.
S.