Engine Block Drain Plug Kit – Fits MerCruiser Marine Engines (Replaces 22-806608A02, 18-4226)

Engine Block Drain Plug Kit – Fits MerCruiser Marine Engines (Replaces 22-806608A02, 18-4226)

This engine block drain plug kit features blue plastic, wing-nut style drain plugs designed for winterizing or draining MerCruiser stern drive and inboard engines. They are used to drain water from the engine cylinder blocks and exhaust manifolds to prevent damage from freezing.

These parts are direct replacements for Sierra 18-4226, MerCruiser 22-806608A02, 22-806608A1, 22-8M0119211, GLM 13992, and Mallory 9-41203, 9-41203-10.

• Installation Method: Simple hand-tightened (wing nut style) installation and removal.
• Sealing: Includes O-rings to ensure a watertight seal.
• Material: Made from durable Nylon plastic to resist corrosion and damage.

Part Number Cross-Reference

Use this table to confirm equivalent part numbers across OEM and aftermarket brands.

Compatible Engine Models

Confirm your engine model/year in the table below. For Mercury owners, here’s a guide to help you identify your engine’s serial/model: Mercury Serial Number Guide. You can also review exploded diagrams to verify part numbers: Mercury Parts Diagrams & Catalog.

Technical Specifications

Package Contents

Package contents may vary slightly between retailers. This typical package configuration includes:

• 5 x Closed Cooling Drain Plugs (Replaces 22-806608A02)
• 5 to 10 x O-Rings (Please verify contents upon receipt, as quantities can differ)

Installation Guide

1. Ensure the engine is turned off and completely cool before starting.
2. Locate the blue plastic drain plugs on the engine block and exhaust manifold(s).
3. Place a suitable container below the drains to catch the water.
4. Carefully unscrew the wing-nut plugs by hand.
5. Allow all water to drain completely from each point.
6. Check the condition of the O-ring on the new plug and ensure it is properly seated.
7. Thread the new plugs into the ports and hand-tighten only until snug. Do not use tools or overtighten, as this can damage the plug or housing.
8. After re-filling with coolant or launching the boat, run the engine and check thoroughly for any leaks around the plugs.

Troubleshooting & FAQ

How do I confirm this fits my engine?

This plug is designed for most MerCruiser stern drive and inboard engines. The most reliable way to confirm fitment is to match your existing part number to those in our cross-reference table (e.g., 22-806608A02, 18-4226). Additionally, verify that the thread size of your current plug is 1/2"-13.

What is the purpose of draining the engine block?

Draining the engine block and manifolds is a critical step for winterization in regions with freezing temperatures. This process removes trapped water that could otherwise freeze, expand, and crack the engine block or exhaust manifolds, leading to expensive and catastrophic damage.

How often should I replace these drain plugs?

Visually inspect the drain plugs and their O-rings each time you perform seasonal maintenance (winterization or recommissioning). We recommend replacing them if you see any signs of cracking, wear, stripped threads, or if the O-ring appears compressed, brittle, or damaged to ensure a reliable seal.

What if my old drain plug was a different color?

While original plugs can come in different colors, the functional specifications are what matter. As long as the thread size (1/2"-13), wing-nut design, and part number cross-reference match your requirements, the color difference does not impact performance.

OEM vs. Aftermarket?

This listing is an aftermarket replacement part (not an OEM component). We build to OEM specifications using comparable-grade materials. Production is done in an ISO9002-certified facility, and each batch is inspected for consistent performance.

How fast do you ship and how much does it cost?

We offer fast global shipping—typically 5–15 days worldwide—and standard shipping is free. Expedited options are available at checkout depending on your location.

What is your warranty and return policy?

This product includes a 1-year warranty against manufacturing defects under normal use. If something goes wrong, contact our support team with your order details. Returns are accepted within our standard return window (unused & in original condition); please see our policy page or reach out for instructions.

Important Notes

• Verify that the product images and specifications match your original part. If discrepancies exist—even if your model is listed—do not proceed with the purchase.
• This product is an aftermarket replacement part and is not an OEM component.
• Professional installation is recommended to ensure safety and optimal performance.

Why Choose JLM MARINE?

• Quality Assured: As a trusted manufacturer for over 20 years, we supply top marine brands globally.
• Fast Global Shipping: Free delivery worldwide in 5–15 days.
• Direct from Manufacturer: Competitive pricing without compromising quality.