Mercury – Gearcase Shim Set – 15-32563A1

The Mercury Quicksilver Gearcase Shim Set 15-32563A1 is an OEM shim kit used to set correct drive shaft bearing position and gearcase preload in compatible MerCruiser drive shaft housing assemblies. These precision shims allow fine adjustment during upper gearcase service, helping establish proper bearing setup, pinion depth, and gear contact pattern.

Key Features

• Genuine Mercury/Quicksilver gearcase shim set
• Part number: 15-32563A1
• Also referenced as 32563A1
• Drive shaft housing top cover bearing shim kit
• OD: 1.750″
• ID: 1.500″
• Designed for 1.7813″ bore applications
• GTIN / UPC: 0745061077386
• Used for bearing preload, gear depth, and contact-pattern adjustment

Drive Compatibility

Commonly used on select MerCruiser Alpha One Generation II drive assemblies in the upper drive shaft housing / top cover bearing area.

Serial Number Fitment Notice

Verify fitment by drive serial number, upper gear housing diagram, bearing configuration, and shim location before ordering. Shim sets are application-specific and should not be substituted by diameter alone.

When This Part Needs Replacement

Use this shim set during upper gearcase rebuilds, bearing replacement, drive shaft housing service, or any repair requiring gear tooth contact pattern and bearing preload adjustment.

Installation Notes

Correct shim selection requires proper Mercury service procedures, measurement tools, and contact-pattern verification. Inspect the tapered roller bearing, bearing race, top cover, gearset, and housing bore before final assembly. Improper shim setup can cause gear noise, heat, accelerated wear, or premature gearcase failure.

Alternate/Superseded Part Numbers

Primary Mercury references: 15-32563A1 and 32563A1. Common aftermarket interchanges include Sierra Marine 18-2282 and Sterndrive Engineering / SEI 98-106-02K.

Parts Desk Insight

Shim kits are not close enough parts. Their job is to position the bearing and gearset precisely, so the correct kit and careful setup are what prevent noisy gears and repeat lower-unit teardown.

Shipping: Ships same or next day for fast Canada wide shipping.