I am having a problem with my Johnson outboard. The engine starts with no problem. When I advance the throttle forward the engine will attempt to stall past 1000 to 1500 RPM. I can resolve the issue by treating the motor as if there was something on the prop or something clogging the intake screens...I back the boat in a hard reverse for 10 seconds or so. Then I am able to go forward with no RPM restriction. But the thing is the water is clear and there is nothing on the prop and nothing clogging the intake screens. The water pump indicator ("pisser") is discharging water. The engine is not overheating...no steady horn alarm. After a full speed run to my destination, I turn the engine off. After a while of fishing, I turn the engine on and it starts immediately. I then attempt to go forward...and back to square one...1000 - 1500 rpm limit...if advance the throttle further...the engine will attempt to stall. I then put it in reverse and the issue goes away again. I just spent $500 in a shop for nothing. They did find oil leaking from the carburetor gasket...they changed out the gaskets and tuned the engine up. The mechanic says he does not know what the problem is when I first brought it in...his shop specializes in Mercury outboards. I had this problem in the late 90's. I took it to an outboard mechanic (regretfully...not in business anymore)...and I remember him taking off the engine shroud and showing me a part he had to replace. Anyway, I am just beside myself over this issue. I plan to take my engine to another shop. Could someone help me with this issue? Thank you.