Sierra O-Ring 18-7153-9 for Mercury Stern Drives (Alpha I, Alpha I SS, Bravo I/II), Pack of 5

The Sierra 18-7153-9 O-Ring is sold in a pack of 5 and is used on a range of Mercury stern drive units, including R/MR/Alpha I, Alpha I SS, Bravo I/II, IA/IB/IC, and II drives, depending on the serial number of the unit. Each application on these drives requires 2 of these o-rings, so a single pack of 5 covers more than one repair with one spare o-ring left over. The o-ring is a small, lightweight sealing component at 0.02 pounds, designed to be used as part of a routine seal replacement or rebuild on the applicable stern drive.

Because fitment depends on the specific stern drive model and its serial number range, buyers should confirm their drive model and serial number before ordering to ensure the 18-7153-9 o-ring is the correct part for their unit. This o-ring is identified by the manufacturer with the internal description code UJ.

Specifications

• Brand: Sierra
• Manufacturer Part Number: 18-7153-9
• Package Quantity: 5 o-rings per pack
• Quantity Required Per Application: 2
• Weight: 0.02 pounds
• UPC: 808282165321
• Category: Mercury Outboard Powerhead Seals & O-Rings
• Oil Seal Description Code: UJ
• Stern Drive Fitment: R/MR/Alpha I, Alpha I SS, Bravo I/II, IA/IB/IC, II

Fitment

• R/MR/Alpha I stern drive, serial number 6225577 and up
• Alpha I SS stern drive, all serial numbers
• Bravo I/II stern drive, serial number B664190 and up
• IA, IB, IC stern drive, serial numbers 1684188 through 2065189
• II stern drive, serial numbers 2398798 through 2671321

Replaces (OEM)

• No cross-reference numbers listed

Frequently Asked Questions

How many o-rings come in the Sierra 18-7153-9 pack? The Sierra 18-7153-9 o-ring is sold in a pack of 5.

How many of these o-rings does one repair need? Each stern drive application listed for the 18-7153-9 o-ring requires 2 o-rings, so one pack of 5 is enough for a repair with one spare left over.

Which stern drives use the 18-7153-9 o-ring? This o-ring fits the R/MR/Alpha I, Alpha I SS, Bravo I/II, IA/IB/IC, and II Mercury stern drives, with fitment depending on the drive's serial number range.

Does the 18-7153-9 o-ring fit the Alpha I SS drive? Yes, the Alpha I SS stern drive uses the 18-7153-9 o-ring across all serial numbers, requiring 2 per application.

What serial number range applies to the R/MR/Alpha I fitment? For the R/MR/Alpha I stern drive, the Sierra 18-7153-9 o-ring applies to serial number 6225577 and up.

Is the 18-7153-9 o-ring compatible with Bravo I/II drives? Yes, Bravo I/II stern drives with serial number B664190 and up use the 18-7153-9 o-ring, 2 per application.

What is the serial number range for the IA, IB, IC fitment? On IA, IB, and IC stern drives, the 18-7153-9 o-ring applies to serial numbers 1684188 through 2065189.

Does this o-ring fit the II stern drive? Yes, the II stern drive uses the 18-7153-9 o-ring on serial numbers 2398798 through 2671321.

How much does the 18-7153-9 o-ring pack weigh? The Sierra 18-7153-9 o-ring pack weighs 0.02 pounds.

What is the UPC for the Sierra 18-7153-9 o-ring pack? The UPC for this o-ring pack is 808282165321.

What is the manufacturer's description code for this o-ring? The 18-7153-9 o-ring is identified internally with the description code UJ.

Is the Sierra 18-7153-9 a genuine Sierra part? Yes, part number 18-7153-9 is a Sierra-branded o-ring sold as a pack of 5.