1987 Force 85 HP Trim/Tilt issues

[steamplant]

The motor tilts fully upwards when pulling it out of the water on the trailer however it slowly lowers by itself. We also noticed that it will not tilt upwards when underway. There are now external oil leaks the engine moves smoothly up and down in the driveway on the trailer. Does this indicate the piston seal rings need replacing? or more likely motor check valves.

Thanks

[Kajun37]

do you have pictures of your 87 85hp force? i just bought one i think it is a 87 or 88..there is no ID plate on it...

[rosco_59]

Sounds like the "O" rings need replaced in the piston

[Dawg2]

You might want to check the check valves in the valve body also. Mine did that and check valve needed rebuilding.Replace oring on outside of check valve.Check valve body will also come apart and is very small oring inside for check ball and spring....Mercury dealer still has these but i matched mine at hydrolic repair shop.