My motor runs fine at full throttle. Have to ithrotle up to get motor to start. I removed the trhree carboratora and took completely apart and soaked in cleaner. I run the boat two to four times a week. The carborator psych were basically clean. I put everything back together. Same result. I replaced the hose from the tank to the motor. Replaced the spark plugs, they looked like burning rick, black. The motor cranks food on hose but when at the lake it is difficult to start with out throttling up.

Well, I worked it out. there was an o ring on the top of the Carburetor where the air mixes. I removed the Carburetor again and cleaned them out. now the motor is running great again.