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Sierra 18-4638 Marine Piston .015 Oversize Starboard Mercury Outboard

Manufacturer

Picture for manufacturer Sierra

Part Number

18-4638
8 reviews
Sale Price

$118.57

3 left at this price

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Usually delivered within 2 days

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Product Details

The Sierra 18-4638 is a .015" oversize starboard piston designed for Mercury outboard engines with 2-ring inline configurations. Engineered as a direct replacement for worn or damaged engine pistons, this oversize piston is used during engine rebuilds where the cylinder bore has been machined to restore a proper fit and seal.

Sierra Marine parts are manufactured to meet or exceed original equipment specifications, ensuring reliable performance and longevity in marine applications. This piston is the ideal solution for engine rebuilds requiring a .015" oversize starboard-side piston for inline Mercury outboards.

Key Features:

  • .015" Oversize — designed for use after cylinder bore has been honed or bored .015" over standard diameter
  • Starboard position — cylinder-specific fitment for multi-cylinder inline Mercury outboard engines
  • 2-ring inline piston design — matches OEM ring configuration
  • Manufactured to meet or exceed original equipment performance standards
  • Part of Sierra Marine's comprehensive internal engine rebuild component line

Sierra 18-4638 is a specialized rebuild component intended for use by experienced marine technicians performing powerhead rebuilds. Always verify bore measurements before selecting piston oversize to ensure proper fit and engine performance.

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Very easy thanks

Found part in stock and not at competitors.

Got exactly what I ordered, when promised, for a great price. Doesn't get any better than that!

I needed it next day air $84 is RIDICLOUS

Best Price on the Net for K&N System for my 2012 HEMI RAM. My Order 18270 is shipping today and I can't wait to get it installed!

Quick and Easy so far.

The best pricing around and great shipping and communication when I reached out to them. Thank you Autoplicity!

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