Description
Mercury Lower Unit Drain & Fill Plug Gasket (81987) – Cross-Ref Yamaha 90430-08003-00
Keep water out of the gearcase and protect your outboard with the genuine Mercury lower unit drain & fill plug gasket. This crush-style seal is designed for the drain and vent screws used during gear lube changes. Replace the gasket each time the screw is removed to help ensure a clean, leak-free seal.
Applications
- Use: Seals the lower unit drain/vent (fill) plug during gear lube service.
- Maintenance: Replace at every gear lube change or whenever the screw is removed.
- Prevention: Helps keep water out and gear lube in to protect gears and bearings.
Design Details
- Crush Gasket: Forms a fresh seal when torqued to spec.
- OEM Fit: Made to match Mercury drain/fill screw dimensions.
- Service Friendly: Simple, inexpensive insurance against gearcase leaks.
Key Facts
- Brand: Mercury
- Item: Lower unit drain & fill plug gasket
- Part No.: 81987
- Cross-Reference: Yamaha 90430-08003-00
- Category: Parts > Gearcase & Seals
Service Notes
- Use a new gasket each time the plug is removed; clean threads and seating surfaces before installation.
- Torque the plug to your engine’s specification and verify for seepage after the first run.
- Dispose of used gear lube responsibly per local regulations.