SUPPLEMENTS 15-38657A1

Function and technical context

Shims—also known as shims—are precision components that regulate critical clearances and tolerances in the power distribution and transmission system of Mercury, Mariner and MerCruiser engines. These parts are placed between moving components to guarantee the correct operation of valves, gears and couplings, ensuring that the mechanical clearances remain within the manufacturer's specifications. Its correct installation is essential to avoid premature wear, abnormal noises, loss of compression and failures in the transmission of forces within the engine.

When to replace this part?

The shims require inspection and replacement when dismantling work is carried out on the engine - particularly in cylinder head overhauling, timing repair or block grinding - as they may suffer from deformation, material hardening or loss of thickness after prolonged operation or thermal exposure. It is recommended to replace these components preventively during any major intervention to ensure that the mechanical clearances are back to specification and avoid costly repairs resulting from incorrect clearances that shorten the life of the engine.

Compatible Mercury Mariner Engines

Equivalent manufacturer part numbers