Mercury – Quicksilver 816575A3 Gear Case Seal Kit | MerCruiser Alpha One Gen II Sterndrives | 816575A3

Overview

Leaks and water intrusion can do real damage to your drive, but the Quicksilver 816575A3 Gear Case Seal Kit helps keep that from happening. Designed for MerCruiser Alpha One Gen II sterndrives, this OEM kit includes every seal, O-ring, and gasket needed to restore a watertight fit and protect your gears from contamination.

Each piece is built to Mercury’s tight tolerances using marine-grade materials that handle constant pressure, vibration, and exposure to oil and saltwater. If you’re servicing or rebuilding your gearcase, this is the right kit to finish the job with factory precision.

Key Features

• Purpose: Replaces worn seals, gaskets, and O-rings to stop leaks and maintain proper oil pressure.
• Fitment: For MerCruiser Alpha One Gen II sterndrives.
• Kit Contents: Includes all critical seals, O-rings, and gaskets for a complete gearcase reseal.
• Durability: Made from marine-grade rubber and composite materials designed for heat and oil resistance.
• OEM Quality: Manufactured to Mercury Marine specifications for exact fit and long-lasting performance.

Engine & Boat Compatibility

• Fits MerCruiser Alpha One Gen II sterndrives
• Common on mid-size runabouts, cruisers, and fishing boats powered by MerCruiser engines

Performance & Practical Benefits

The 816575A3 seal kit keeps your lower unit protected from water intrusion while maintaining the correct internal oil pressure. Old seals can dry out or crack, leading to leaks that let water in or gear lube out — both of which shorten drive life. Replacing them with OEM parts restores full protection and ensures smooth operation at every RPM.

Mercury’s sealing materials are designed specifically for marine conditions, resisting salt, oil, and temperature swings. With fresh seals in place, your drive stays clean inside, your gears stay lubricated, and your maintenance schedule stays predictable.

Why Buy OEM

Gearcase sealing is not the place to take chances. Mercury’s OEM kits are made with exact fitment in mind — something aftermarket versions often miss. Even a slight size mismatch can cause leaks or improper pressure balance.

A genuine Quicksilver kit ensures each gasket and O-ring is the correct shape, thickness, and material for your specific drive. It’s the only way to guarantee the kind of performance and reliability Mercury designed into your sterndrive from day one.

FAQ

Q1: What drives does this kit fit?
A: It’s designed for MerCruiser Alpha One Gen II sterndrives.

Q2: What’s included in the kit?
A: A full set of seals, O-rings, and gaskets for resealing the gearcase housing.

Q3: Can I install it myself?
A: Yes, if you’re comfortable servicing lower units. Otherwise, a marine technician can install it quickly during maintenance.

Q4: How often should I replace seals?
A: Replace them whenever you rebuild the lower unit or if you notice water in the gear oil.

Q5: Why OEM instead of aftermarket?
A: OEM seals are made for your specific drive and last longer, ensuring leak-free performance and correct oil retention.