SPRING NUT 90183-02M03

Function and technical context

This spring nut is a critical fastening component in Yamaha and Mercury marine engines, responsible for securing elements subjected to constant vibration and dynamic loads during the operation of the propeller. It works on the engine's mechanical fastening system, ensuring that vital components remain firm even under rough running conditions and sudden acceleration. Its function is to guarantee a stable and long-lasting joint through the action of the integrated spring washer, which maintains the tightening tension over time and prevents progressive loosening that could lead to loss of tightness, water ingress or disconnection of critical systems.

When to replace this part?

Although spring nuts do not show obvious signs of failure until final collapse, they should be inspected at each seasonal inspection to verify that they maintain their tightening tension and that the washer has not lost elasticity. If during maintenance it is detected that the nut rotates without resistance, that it has left rust or corrosion marks around its seat, or that the component it holds has suffered abnormal movement or vibration, it must be replaced immediately. Preventative replacement of fatigued spring nuts during major maintenance tasks prevents unforeseen breakdowns at sea and ensures the structural integrity of the engine throughout the sailing season.

Equivalent manufacturer part numbers