S2K Commerce - Products Dropdown
Actions
S2K Commerce - Order Entry
Actions
20839
20839T
62699
F523143
F523143
12578
12578
12578T
18-1113
18-1113
18-1121
22980
69220
69220
69220T
F84225
F84250
77420A1
8M0166756
12596A2
12596A4
12596T2
8M0168901
Fits Select Mercury 25-70HP Gearcase Applications
Designed for Mercury and Mariner lower unit bearing carrier assemblies. The Mercury 21700 Bearing, also listed as 31-21700, is a needle / roller bearing used in the gearcase bearing carrier area to support the propeller shaft.
Compatibility
This bearing is used across many Mercury and Mariner small to midrange outboard gearcases. OEM where-used data shows applications across multiple 25-70HP gearcase families, including 2-stroke, 4-stroke, BigFoot, and Jet models.
Application Chart
| Brand | Engine Family | Horsepower | System | Component |
|---|---|---|---|---|
| Mercury / Mariner | Small 4-Stroke Outboards | 25-30 HP | Gearcase / Lower Unit | Bearing Carrier / Prop Shaft Bearing |
| Mercury / Mariner | 2-Cyl / 3-Cyl Outboards | 35-40 HP | Gearcase / Lower Unit | Bearing Carrier / Prop Shaft Bearing |
| Mercury / Mariner | 3-Cyl / 4-Cyl Outboards | 45-60 HP | Gearcase / Lower Unit | Bearing Carrier / Prop Shaft Bearing |
| Mercury / Mariner | BigFoot / 4-Stroke Models | 40-60 HP | Gearcase / Lower Unit | Bearing Carrier / Prop Shaft Bearing |
| Mercury / Mariner | 70HP 3-Cyl Outboards | 70 HP | Gearcase / Lower Unit | Bearing Carrier / Prop Shaft Bearing |
| Mercury / Mariner | Jet Models | 30-45 Jet | Gearcase / Jet Drive | Bearing Carrier / Prop Shaft Bearing |
Always confirm compatibility using your engine serial number, gearcase type, and existing part number before ordering.
Part Numbers & Cross References
| Reference Type | Part Number |
|---|---|
| Mercury OEM Part | 21700 |
| Mercury OEM Part | 31-21700 |
| Cross Reference # | 18-1095 |
| Cross Reference # | 93-263-12 |
| Cross Reference # | 11428 |
What This Part Is Used For
This bearing is used in the lower unit bearing carrier to support the propeller shaft. A properly functioning bearing helps maintain smooth prop shaft rotation and proper gearcase operation.
Bearings are commonly inspected or replaced during lower unit rebuilds, bearing carrier service, prop shaft repair, or when gearcase noise, vibration, or wear is found.
Frequently Asked Questions
What does Mercury 21700 fit?
This bearing fits select Mercury and Mariner small to midrange gearcases, commonly in the 25-70HP range. Always verify by serial number and gearcase diagram.
Where is this bearing used?
It is used in the lower unit bearing carrier area to support the propeller shaft.
Is 21700 the same as 31-21700?
Yes. Mercury commonly lists this bearing as 31-21700.
When should this bearing be replaced?
Replace it during lower unit rebuilds or when wear, noise, corrosion, or prop shaft bearing damage is found.
Dealer Discounts & Store Policies
Dealer / Marine Industry Discounts
Are you a marine dealer or technician? We offer dealer pricing for qualified businesses.
Shipping Policy
- Free shipping on orders over $100 (continental U.S.)
- Ships via UPS, USPS, and FedEx
- 5:30 PM EST daily cutoff
- Typical delivery 1–5 business days
30-Day Return Policy
- Returns within 30 days
- Items must be unused and in original packaging
- Return authorization is required before sending items back
Contact Us
Phone: 941-721-3000
Searchable Part Numbers
Part Number: 21700
Cross Reference #: 31-21700, 18-1095, 93-263-12, 11428
Common Search Terms: Mercury 21700 bearing, Mercury 31-21700 bearing, Mercury bearing carrier bearing, Mercury prop shaft bearing
848840A1
848840T1
818290A8
818290T8
F506225
F506250
18-1170
8M0103476
812767A1