6L8-G3118-01 BUTTERFLIES

Function and technical context

The 6L8-G3118-01 wing nuts are critical fastening components in the transmission and coupling system of Yamaha and Tohatsu outboard motors. These parts work on the coupling between the crankshaft and the propeller, ensuring reliable and slip-free power transmission. Its structural integrity is essential to maintain the correct alignment of the propulsion shaft and avoid abnormal vibrations that could compromise navigation stability and accelerate the wear of adjacent bearings.

When to replace this part?

The wing nuts require replacement when visible wear, plastic deformation or fractures in the geometry of the housings are observed, symptoms that manifest themselves with shaft vibrations, metallic noise during acceleration or loss of propeller alignment. It is recommended to inspect these parts at each seasonal inspection, especially if the boat has navigated in areas with high salinity or has suffered impacts against submerged objects. Replacing the wing nuts preventively avoids cascade damage that would affect bearings, seals and the crankshaft itself, repairs that are much more expensive in terms of money and downtime.

Engine Compatibility Table

Equivalent manufacturer part numbers