1985 OMC 65, 100 and 155 HP Models Commercial Service Manual, PN 507450-D, Page 390Get this manual
Oil level The oil level is checked at the reservoir fill plug after all air has been removed from the unit and when the tilt cylinder and trim cylinders are fully extended Unit should be in vertical position Troubleshooting Power Trim and Tilt Unit 100 and 155
External Inspection Check the items listed below prior to troubleshooting the trim tilt systemIn many cases, test of the "easy things" first will pinpoint the defective item and save you hours of valuable troubleshooting time1Visual InspectionLook for indications of external oil leaksCorrect the cause if leaks are noted2Proper Reservoir Oil LevelWith the motor fully tilted up, the fluid level should be even with the bottom of the fill plug threads The only fluids approved for use in the trim and tilt reservoir are OMC Power Trim and Tilt Fluid or "Dexron" Automatic Transmission Fluid3Manual Release Valve the manual release valve by tightening the screw to torque of 5-6 Nm (45-55 inIbs4Mechanical BindingInspect stern brackets for binding with swivel brackets in thrust rod areaCheck the torque on the tilt tube nut 32-34 Nm (24-26 ftIbs then back off 18 to 14 turn after torquing and inspect for bent rods on the trim and ti It cyl inders5Unit Locked in Full Tilt PositionTrailering in the tilt position with trim rods extended can cause hydraulic "lock up Check for malfunctioning expansion relief valve