Mercury 12-191833 – Drain Plug Screw Seal Gasket

OEM Gearcase Drain/Fill Screw Seal | Factory Composite Washer | For Mercury, Mariner & MerCruiser

The Mercury 12-191833 is an original equipment gasket designed for the 3/8–16 gearcase drain or fill screw. This composite washer, typically blue in color, provides a reliable, leak-free seal between the screw and the gearcase. It is widely used on many Mercury, Mariner, and MerCruiser outboards and stern drives, excluding Japanese-built models.

Key Features

• Type: Composite gasket seal for gearcase drain/fill screw
• Thread Size: 3/8–16 (standard for most Mercury gearcase drains)
• Color: Blue
• OEM Quality: Genuine Mercury factory part for precise fit and performance

Why Use the Mercury 12-191833 Seal?

• Exact Fit: Manufactured to Mercury’s specifications for proper alignment and sealing
• Marine-Rated: Built to withstand exposure to oil, water, and harsh marine environments
• Essential Maintenance Part: Prevents water intrusion and gearcase damage during routine service

Frequently Asked Questions

Q: What engines does this part fit?
A: It fits many Mercury, Mariner, and MerCruiser outboards and stern drives that use a 3/8–16 drain/fill screw, excluding Japanese-made models.

Q: Can it be used with other brands?
A: Yes. It is interchangeable with equivalent gaskets from Sierra, Quicksilver, and other marine parts suppliers, as long as the size matches.

Q: Why is this part important?
A: Without it, the drain/fill screw can leak, leading to water entering the gearcase and causing serious mechanical damage.

• Supersessions
  12-8M0187157