This is my first post. I have a 90 HP 2002 Mercury 2-cycle that runs like a bucking bronco at idle and at speeds under 2,300 RPM. I cleaned it with sea foam, and with Mercury carburetor cleaning. No help. I changed the plugs, no help. So I took it to the Marine shop and they cleaned the carburetor, drained the tank, dried the tank, filled the tank with Marine grade fuel and accepted $530 in payment. No help. I then called the factory and got a listing for an authorized dealer. They again, cleaned the carburetors, installed new jets, replaced wires and plugs, tuned up the motor and charged $630. No help. I am at the point now of using this engine as an expensive boat anchor. Both shops are shaking their head and saying they do not know what the problem is. Even the authorized dealer is saying the same thing. Thus my post. The motor has maybe 300 hours on it. It still smokes and bucks at idle and under 2,300 RPM. What are my options now other than a new motor?
