KEY 90280-03024

Function and technical context

The cotter pin is a critical fastening element in Yamaha marine engine power transmission systems. This part works at the junction between the drive shaft and the rotating components, ensuring that there is no relative slip between both parts during engine operation. Its correct installation and condition guarantees efficient transmission of torque and prevents moving elements from disengaging under load, which could cause loss of thrust, abnormal vibrations or catastrophic damage to the gearbox.

When to replace this part?

Keys wear or fracture when torsional stresses exceed their load capacity, especially after years of operation in salt water or under conditions of harsh acceleration and frequent gear changes. If during navigation you detect vibrations in the transmission area, difficulty engaging gears or irregular metallic sounds in the shaft, it is a sign that the key has lost its locking function. It is recommended that this part be inspected and replaced preventatively during each seasonal maintenance check, especially if the engine has accumulated more than 500 hours of operation; Changing it preventively avoids larger repairs in the open sea.

Equivalent manufacturer part numbers