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Sierra 18-3902 Piston Ring Set for Mercury/Mariner Outboard Motors

Manufacturer

Picture for manufacturer Sierra

Part Number

18-3902
18 reviews
Sale Price

$30.31

3 left at this price

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Usually delivered within 2 days

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No Hassle Returns

No Hassle Returns

Live-in-stock inventory

Live-in-stock inventory

Fitment guaranteed

Fitment guaranteed

Product Details

The Sierra 18-3902 is a standard-bore piston ring set engineered as a direct replacement for Mercury and Mariner outboard engines. Designed for 3-ring pistons with a 2.875-inch bore size, this ring set delivers reliable sealing performance and meets or exceeds the original equipment specifications it replaces.

Key Features:

  • Standard bore size: 2.875 inches
  • Designed for 3-ring piston applications
  • Meets or exceeds OEM specifications for fit, form, and function
  • Direct replacement for Mercury Marine OEM part numbers
  • Backed by Sierra's manufacturer warranty covering defects in workmanship and materials

OEM Cross-Reference Part Numbers:

  • Mercury Marine: 39-78816A12
  • Mercury Marine: 39-45155A12
  • Mallory: 9-54217

Sierra International is a leading supplier of marine engine and drive parts, offering comprehensive coverage across all major engine brands. The Sierra 18-3902 piston ring set is the trusted aftermarket choice for technicians and boat owners performing engine rebuilds or top-end service on Mercury and Mariner outboard powerheads.

Great price. Easy to use site

Easy transition, l am happy thank you

10 out of 10 will buy again!

Superior Shipping Time & The Product Was Great!!!

The order process was easy and the product arrived quickly.

Easy to order, had the part I needed.

Easy

Easy shopping

Very Convenient...Although this is only half the battle

good

Fast and easy. Love the PayPal option.

emailed you yesterday and received a response shortly afterword.

Wow, first time I ordered and they hit a homerun with me!! Shipped same day I ordered AND was the cheapest option I had including shipping. I'll be back. Thanks for the great service!!

Autoplicity agent was very helpful over the phone. He answered all my questions & even did some research to make me feel comfortable I was getting the appropriate parts I needed for my car. I was very pleased & will shop Autoplicity again.

was fast and simple

they had the lowest price on the window pillars i was looking for<br>for my 2012 dodge ram they also gave me 25% off shipping there customer service was helpful and pleasant i got the best deal on the planet thank you autoplicity

Easy

These people had the lowest price on the Weathertech floor mats for my new Jeep Wrangler. Got them quick with no issues whatsoever! I will for sure be shopping with Autoplictiy in the future! PS...My order number is 910

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