8164641 Shift Shaft Oil Seal — OEM Mercury/Mariner Lower Unit Seal

The OEM Shift Shaft Oil Seal 8164641 is a critical lower unit component used by Mercury/Mariner outboard engines. It seals the gearcase around the shift shaft, preventing water intrusion and maintaining correct gear oil retention.
This seal fits parts numbers including 8M0204708, 816461, 816464, 8164641, 82257M, 85223, 85581 , 916464, 93106-09014-00

It’s commonly installed when you find water in the gearcase, see oil leaking from lower housing, or experience gear-shifting problems. A worn or damaged seal puts internal gears and bearings at risk of corrosion or damage.

Installation is simple: remove the lower unit, place the shift shaft in neutral, remove the old seal, and press in the new seal flush. Ensure the lip faces the oil side and use marine-grade sealant or a new washer as required.

Shift Shaft Seal 8164641

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