YAMAHA VALVE SEAT WASHER 68T-12116-00

Function and technical context

The valve seat washer is an essential component of the timing system in Yamaha four-stroke engines, where it acts as a sealing element and structural support at the base of each valve. This piece guarantees a perfect seal between the valve and its seat in the cylinder head, preventing combustion gas leaks into the engine crankcase and preventing oil from entering the intake and exhaust ducts. Its correct condition maintains adequate compression in the cylinders, ensures the efficiency of the combustion process and preserves the integrity of the lubrication system. Without a washer in optimal condition, the engine experiences loss of power, irregular fuel consumption and risk of accelerated deterioration in cylinders and cylinder head.

When to replace this part?

Valve seat washers require inspection during each cylinder head intervention or when symptoms of valve leaks are detected, such as unstable ignition, bluish smoke in the exhaust or progressive loss of compression in specific cylinders. Although there is no fixed predetermined replacement interval, it is advisable to replace them preventively whenever timing work is carried out or the cylinder head is lifted, as the cost of the part is minimal compared to the potential damage resulting from poor sealing over years of boating. This preventive practice avoids costly repairs and ensures proper engine operation in any navigation conditions.

Equivalent manufacturer part numbers