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Too many old, reused, and worn-out Nyloc nuts loosen causing Mercury High Performance lower units and gearcases to work their way free.


We've seen too many wrongly sized washers used to secure gearcases that have gotten wedged or gone missing. 


The result can be a vibration, broken cavitation plate, lost gearcase, or worse.


This Speedmaster Fastener Kit for the Mercury Racing Super Speedmaster SSM #4 or #6 (Studs-Down) Kit; includes all-new stainless Nyloc nuts, OEM spec thick washers in stainless, and the stainless bolt required to swap out your existing hardware.


Part Numbers

11-859116, 12-35935


Includes one (1) Speedmaster Fastener Kit for the SSM #4 or #6 with sixteen (16) pieces.


Contact Mike Hill at

16 Lower Unit Washers + Nuts Kit for SSM #4 #6

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