Tilt and Trim Question

My 1981 Mercury 115 inline 6 has a power tilt and trim system that I know very little about. when i first bought the boat i tried it out and the tilt seemed to work fine. The guy said he replaced one of the cylinders and it does look newer. When i got it home I took the transom saver off and the motor went to the fully down position. Now it does not go up or down. I have checked the fluid levels and they are fine in the resevior. When I try to use the tilt it makes a sound like the pump is running, but not the sound it originally made. I really dont quite understand the knob that has manual lock and that stuff. The guy said he never bled the system so I am wondering if that is the problem. If so can I get a quick review on how to do that.

Re: Tilt and Trim Question

It sounds like you have the 2 cylinder, external pump model PTT. If so, you need to manually bleed the trim cylinders. First fill the resvoir with either ATF fluid or SAE 5W-30 motor oil, whatever it already has. Now remove one of the bleed screws on top of the trim cylinder. Run the pump in the down position, until oil shoots out the bleed screw hole, w/o any trapped air. Install the screw. Repeat with the other cylinder.

Now remove the trim cylinder from the lower and upper mounts. Leave the trim hoses atached. Face the part of the cylinder where the hoses attach directly upward. Now remove one of the bleed screw next to where the hoses attach. Run the trim motor in the up direction, and watch for oil to shoot out. When the oil has no air, install the bleed screw, and repeat with the other cylinder. Reinstall the trim cylinders and refill the resvoir.