My 1990 mercury mariner 115 will trim up and down but when you trim it up the motor slowly falls back down to the tilt tabs. Anyone ever had this problem before. The reservoir is full of hydraulic fluid.
no mechanic at all!!!! seems like if you have no fluid leaking anywhere, its got to be something electrical allowing the motor to trim back down on its own???? like a short in a switch or whatever???? good luck!!!