Marine replacement parts, CKANDAY Lower Unit Drain Plug Seal Gasket, keep gearcase oil sealed and prevent seawater ingress to avoid costly lower-unit damage. Practical reassurance for boat owners who carry out routine maintenance and want reliable spares aboard. Is a compact kit of correctly sized gaskets the sensible spare to keep on board?
⚡ At a Glance
- • Sealing Performance: Non-asbestos sealing material resists oil seepage and reduces water ingress
- • Best for: Owners of boats with 3/8-16 lower unit drain and fill screws on Mercury, Mercruiser and similar outboards
- • Not ideal for: Lower units on certain Japanese-model engines
Fits 3/8-16 drain and fill screws with an outside diameter of 14.2 mm and inner diameter of 9 mm. Kit contains fifteen gaskets compatible with many Mercury and Mercruiser lower units.
Leak prevention - with premium non-asbestos sealing material
Denser non-asbestos fibre forms a tighter barrier around the 3/8-16 drain/fill screw seat, reducing permeability compared with standard seals. The construction limits both oil seepage and the chance of seawater working past the washer.
A secure seal helps protect the gearcase from water contamination and keeps gear oil where it belongs during use and storage.
Accurate fit across common makes - thanks to 3/8-16 sizing and measured diameters
Manufactured to match the 3/8-16 drain/fill screw standard, with an outside diameter of 14.2 mm and inner diameter of 9 mm. Designed to be interchangeable with older yellow and red fibre gasket types used in many OEMs.
Correct sizing makes installation straightforward and reduces the risk of leaks caused by incorrect washers or reused old seals.
Plenty of spares for maintenance - with a 15-piece kit
The pack contains fifteen identical gaskets, allowing multiple service intervals or servicing several boats without sourcing extra parts. Supplying fresh seals eliminates reliance on compressed or aged washers that compromise the seal.
Useful for routine servicing and pre-season checks, keeping owners ready for unexpected leaks or scheduled drain replacements.
✨ The 4 Key Reasons for CKANDAY Lower Unit Drain Plug Seal Gasket
- Comparable to branded seals - matches branded quality while remaining a cost-effective option
- Interchangeable with legacy gaskets - fits older yellow and red fibre seal applications without changes
- Suitable for lower units and seawater pumps - versatile across common maintenance tasks and installations
- Durable fibre construction - holds a tight seat under drain screws for reliable long-term sealing
📋 Technical Details at a Glance
- Category: Automotive Parts and Accessories - Lower unit drain plug seals
- Thread size: 3/8-16
- Outside diameter: 14.2 mm
- Inner diameter: 9 mm
- Material: Non-asbestos sealing material
❓ Frequently Asked Questions
Q: Are these seals compatible with Mercury and Mercruiser lower units?
A: Yes, compatibility is stated for Mercury and Mercruiser and for many other inboard and outboard manufacturers that use the 3/8-16 drain/fill screw.
Q: What are the gasket dimensions and thread size?
A: Outside diameter is 14.2 mm, inner diameter is 9 mm, and the gaskets fit 3/8-16 drain and fill screws.
Q: Can these be used as replacements for older part numbers?
A: Yes, the gaskets are described as interchangeable with older yellow and red fibre gaskets and listed as replacements for several legacy part numbers.
🏆 Our Verdict
Well suited to DIY boat owners and marine technicians who need reliable replacements for common lower-unit drain screws. Dense non-asbestos construction, cross-compatible sizing and a generous pack size make the kit a practical spare parts choice. Given the interchangeability with older part numbers and everyday usefulness during servicing, the kit represents sensible long-term value for routine maintenance.
