REVERSE GEAR PIN 57521-93910

Function and technical context

The reverse gear is the gear responsible for reversing the direction of rotation of the propeller within the lower unit gearbox of the outboard, making the reverse maneuver possible. It works in the lower drive system in combination with the forward gear pinion and the drive pinion of the horizontal propulsion shaft, transferring the engine torque to the propeller in the opposite direction to the forward direction. The deterioration of this gear directly compromises the maneuverability of the boat: a pinion in poor condition causes poor reverse engagement, loss of traction in reverse gear, metallic noises in the lower unit or even the inability to select said gear, with the risk that this entails in docking and port maneuvers. The reference 57521-93910 has been updated by Suzuki with the reference 57521-90L00, which is the current version of the same component.

When to replace this part?

The most common signs of reverse sprocket wear are difficulty or hardness when selecting reverse gear, knocking and clicking when engaging reverse, and abnormal vibrations perceived in the control knob when engaging said gear; In advanced cases the gear teeth may show pitting, wear on the flanks or even breakage. The preventive maintenance interval for the lower unit oil—generally every season or every 100 hours of navigation—is decisive for the useful life of this pinion, since lubricant contaminated with water or metal particles accelerates the wear of the gear flanks. Checking the condition of this component at each stranding or oil change of the conical group makes it possible to detect deterioration in time and prevent a transmission breakdown from leaving the boat inoperative at the most critical moment.

Compatible Johnson/Evinrude Engines