SIERRA Internal Engine 18-3916 Piston Rings For Mercury/Mariner Outboard Motors

Complete engine repairs with quality piston rings from Sierra Marine.

Sierra piston rings are machined to perfectly match engine component mating surfaces, 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.

Key Features

• Engineered to meet or exceed manufacturer specifications
• Replaces Mercury Marine 39-78811A12
• OEM performance at a value price
• Often more readily available than OEM piston rings

The Sierra Engine Parts Selector

We offer a wide variety of other engine parts manufactured by Sierra. To see if we have the part you need, see our Engine Parts Selector, where you can search by engine make, serial number and model or year of manufacture.

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.