SIERRA Internal Engine 18-3921 Piston Ring For Mercury/Mariner Outboards

Complete engine repairs with quality parts from Sierra Marine.

Sierra parts are machined to perfectly match the OEM part they replace, which gives trained technicians and DIY mechanics alike the confidence that the job will be done right the first time. For over 50 years, Sierra has supplied the best aftermarket parts in the marine industry—so boaters can enjoy the best of times on the water.

Sierra 18-3921 replaces the following manufacturer part numbers:

• GLM: 14240
• Mallory: 9-54233
• Mercury Marine: 39-93481A12
• Wiseco: 3125KD

Key Features

• Engineered to meet or exceed manufacturer specifications
• OEM performance at a value price
• Often more readily available than OEM parts

Find the right part for your application.

For help in selecting the correct part for your engine application or to confirm this is the correct part, please visit the Sierra Engine Parts Selector, where you can search by OEM part number, Sierra part number, Brand, Engine model, Year, Horsepower, or Serial number.

Order with confidence!

The Sierra engine parts we sell are backed by Sierra’s Limited Customer Satisfaction Warranty—one of the best in the business. Sierra warranties their engine parts to be free of defects in workmanship and materials for the useful life of the product. Subject to limitations, if a Sierra product fails to comply with the Warranty, Sierra will repair or replace the defective product free of charge.