After using my outboard to exit and enter the marina, I raise the engine out of the water and tilt it to the 1st position. I'm getting a muddy coloed oil discharge from the water discharge ports above the anti-cavitation plate. It runs down a few inches and stops. Local shop told me the engine is running rich and to turn the "low speed adjusting knob" 1/4 turn clockwise (lean). I did and still get the discharge. NOTE: Engine starts and runs great at all speeds. Any ideas?