Mercury Marine locking plate for driveshaft housing – 16121 is an original OEM spare part that acts as a retention component in the driveshaft housing and gearcase on compatible smaller outboard engines. The part is registered as a retainer in Mercury Marine's spare parts documentation.
The locking plate is used on documented Mercury 4 and 5 hp 2-stroke engines as well as Mercury 4, 5 and 6 hp 4-stroke engines. It is also documented for the Mercury 5 hp 4-stroke JCI from serial number 0R560794 and up.
Compatibility also includes selected Mercury and Mariner 4 and 5 hp engines with serial number ranges 9589154-0P016999 and 0A855097-0G710612. For Japanese-manufactured 1-cylinder Mercury/Mariner 4 and 5 hp engines, the ranges 9477830-9589153 and 0A809601-0A855096 apply.
The part number is 16121, and Mercury documentation specifies one unit in the relevant driveshaft housing assembly. Always check the engine's model, serial number and existing part number before ordering, as compatibility depends on the specific serial number range.
Key featuresOriginal Mercury Marine OEM spare part
Part number: 16121
Product type: Locking plate/retainer
Location: Driveshaft housing and gearcase
For documented Mercury 4-6 hp engines
For documented Mariner 4-5 hp engines
Fits selected 2-stroke and 4-stroke engines
Quantity specified in spare parts documentation: 1
Check engine serial number before purchase
