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Sierra 18-2642 Lower Unit Gearcase Seal Kit for Mercury/Mariner 200-300 HP Outboards

Manufacturer

Picture for manufacturer Sierra

Part Number

18-2642
12 reviews
Sale Price

$40.97

In Stock (8)

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Usually delivered within 2 days

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Fitment guaranteed

Fitment guaranteed

Product Details

The Sierra 18-2642 is a lower unit gearcase seal kit engineered as a direct replacement for Mercury and Mariner outboard motors. It directly replaces Mercury OEM part number 26-816575A5 and is cross-referenced with GLM 87513 and Mallory 9-74209, making it a trusted aftermarket solution for high-horsepower V6 3.0L gearcase service.

This kit is designed for use on Mercury and Mariner 200–300 HP 3.0L Carbureted and EFI outboard engines. It contains all the seals, O-rings, and gaskets necessary to perform a complete lower unit gearcase rebuild, helping restore proper gear oil retention and preventing water intrusion into the lower unit.

Key Features:

  • Direct replacement for Mercury OEM part 26-816575A5
  • Includes all seals, O-rings, and gaskets required for a complete lower unit overhaul
  • Designed for Mercury and Mariner V6 3.0L Carb and EFI high-horsepower outboards (200–300 HP)
  • Cross-references: GLM 87513, Mallory 9-74209
  • Manufactured by Sierra International, a leading supplier of marine aftermarket parts
  • Helps prevent gear lube leaks and water intrusion into the gearcase

Sierra International is a trusted name in marine aftermarket components. The 18-2642 seal kit is built to meet or exceed OEM specifications, ensuring a reliable, long-lasting gearcase rebuild for your Mercury or Mariner outboard.

I ordered an exhaust setup (headers and a cat-back) late monday night, an it was shipped on wednesday. Thanks for a fast transaction Autoplicity!

quick and easy

Very easy and received a surprise 20% off shipping.

Easy to use

Very competive prices, even with shipping costs. Looking forward to using Autoplicity again in the near future.

Trustworthy seller. This is my second order. Got it quickly. good job!

Quick and easy to check out

Great price Awesome so far

Good price

This was an excellent transaction! I ordered parts on Sunday and they arrived tuesday afternoon. Low price, no fuss and super fast. Thanks Autoplicity..........

I ordered a Tokico shock and everything went great. Shipping took a few days and it came in good condition and at a great price!

The order process was fast and easy. I was able to determine the part I wanted with the help of their sales department. I purchased my H&R lowering springs for less then I could find anywhere else and I also got a great deal on my EBC Green Stuff brake pads. The following day however i noticed a descrepency in my shipping address in the confirmation e-mail they sent me. After being dicsconnected multiple times and at least 6 seperate attempts to reach the shipping department i was finally connected and assured that the information that they had was correct. It did seem like a waste of 45 minutes but at least I know that the parts are going to be delivered to the correct address.

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