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There are two main types of power tilt and trim motors and pumps that are designed for recreational boats that have an outboard or a stern drive.

Older power tilt and trim systems use an electric tilt motor and a mechanical lifting device. On stern drives, the electric motor turns a worm gear and uses a wet clutch pack to tilt the drive unit and lock it into place.

Tilt & Trim Motors and Pumps

More modern boats, such as Johnson, Evinrude, Mercruiser and Volvo Penta stern drives, commonly use an electric / hydraulic power trim and tilt system. This arrangement consists of a 12-volt electric motor with a reservoir and a hydraulic pump or valve body.

Problems with the hydraulic pump or valve body manifest themselves when the trim and tilt motor seems to be functioning properly, but the engine or drive unit won’t stay trimmed, or bleeds when in the upside down position.

In this case, boaters are advised to replace their trim and tilt hydraulic pump and fill the reservoir with the proper power trim and tilt fluid. Captains are cautioned to not use transmission fluid, as the detergents in this solution can wear on the systems’ seals.

Visit the Replacing Power Trim and Tilt Systems comprehensive article to aid in trouble shooting and the common problems with power tilt and trim systems.