I recently purchased a 1993 90HP Johnson outboard. The motor has very low hours on it and it has not been run in approximatley three years. Before taking it out for the first time I took it to my local repiar shop to have them look over it and do a general tune-up. The repair shop changed the spark plugs, changed the oil in the lower unit, pumped and drained the old gas, and they said that thy cleaned the carborator. When I took it out on the water for the first time the engine would idle rough and it smoked a lot. When driving it at about 3/4 throttle it would hestiate and jump like it was not getting enough fuel. Before taking it out the next day I poured a can of SeaFoam in the gas tank. That time it seemed to improve the hesitation some but it would not idle as well. The second time I took the boat out it would not go as fast as the frst time but it felt like it ran smoother. Do you think I am correct in assuming that the carborator probably needs additional cleaning to to cure the hesitation and improve the idling or could there be a bigger problem?Thanks for any help.