LOWER PIN KIT OMC 986979

Function and technical context

The lower pinion kit for OMC engines is part of the transmission system of the tail or propulsion unit, being responsible for transferring the engine torque from the vertical axis to the propeller shaft through a set of conical gears located in the lower section of the gearbox. These sprockets work under conditions of high mechanical load and in permanent contact with the transmission oil, so their condition is decisive for the correct functioning of the drive assembly. Advanced wear or breakage of any of the kit's sprockets can cause progressive loss of traction, metallic noises in the propulsion and even complete blocking of the transmission, leaving the boat without propulsion. Replacing the complete kit, instead of individual parts, ensures wear balance between all elements of the lower gear train and prolongs the life of the assembly.

When to replace this part?

The most common symptoms that indicate wear or failure of the lower sprockets are: metallic noise or rattling in the tail area when engaging or during fully loaded navigation, difficulty in engaging forward or reverse gear, abnormal vibration transmitted to the propeller control and the presence of metal chips in the transmission oil when changing the oil. It is recommended to check the condition of the lower sprockets at each transmission oil change, which in Johnson and Evinrude engines is usually done annually or every boating season. Replacing the kit preventively at the first symptoms prevents secondary damage to the propeller shaft and gearbox housing, repairs that are considerably more expensive.

Equivalent manufacturer part numbers