Manifold Engine Block Drain Plug Kit – Fits MerCruiser/Mercury Inboard Engines (Replaces 22-806608A02, Sierra 18-4226)

Manifold Engine Block Drain Plug Kit – Fits MerCruiser/Mercury Inboard Engines

This aftermarket drain plug kit is designed for MerCruiser/Mercury inboard and stern drive engines. It provides a reliable solution for draining the engine block and manifold in most V6 and V8 applications that utilize a closed cooling system.

This kit serves as a direct replacement for several OEM and aftermarket part numbers, including Sierra 18-4226, MerCruiser 22-806608A02 and 22-806608A1, GLM 13992, and Malloy 9-41203 and 9-41203-10.

• Simple Installation: Plugs are a wingnut style, designed to be hand-tightened.
• Durable Material: Constructed from high-quality blue nylon/plastic for corrosion resistance.
• Complete Kit: Includes new O-rings for a secure, leak-free seal.

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

This product is available in two package sizes. Please confirm your selection before ordering.

5-Pack Option:

• 5 x Manifold Engine Block Drain Plugs (Replaces 22-806608A02)
• 5 x O-rings

10-Pack Option:

• 10 x Manifold Engine Block Drain Plugs (Replaces 22-806608A02)
• 10 x O-rings

Installation Guide

1. Ensure the engine is completely cool before starting.
2. Locate the existing drain plugs on the engine block and/or exhaust manifolds.
3. Place a suitable container underneath the plugs to catch the draining fluid.
4. Carefully unscrew the old plugs by hand.
5. Clean the threads on the block or manifold to remove any debris or sealant residue.
6. Place the new O-ring onto the new drain plug.
7. Screw the new wingnut-style plug in by hand until it is snug. Do not overtighten, as this can damage the plug or threads.
8. Repeat the process for all drain plugs being replaced.
9. Refill the cooling system according to your engine manufacturer's specifications.
10. Start the engine and let it reach operating temperature, carefully checking for any leaks around the new plugs.

Troubleshooting & FAQ

Q: How do I confirm this plug fits my engine?
A: This plug fits most MerCruiser V6 and V8 inboard engines with closed cooling systems. The most reliable method is to match your old part's number to our cross-reference list, which includes Sierra 18-4226 and MerCruiser 22-806608A02.

Q: What is the difference between this drain plug and the OEM version?
A: This is a high-quality aftermarket part designed to meet or exceed OEM specifications. It is made from a durable, corrosion-resistant nylon/plastic composite, similar to the original, but offered at a more competitive price point.

Q: Why is my new drain plug leaking?
A: Leaks are typically caused by one of three issues: an improperly seated O-ring, debris on the threads, or overtightening. Ensure the O-ring is correctly in place, the mating surface is clean, and that the plug is only hand-tightened until snug. Cranking it down with force can damage the seal or the plug itself.

Q: How often should I replace my drain plugs?
A: We recommend inspecting your drain plugs during routine seasonal maintenance or winterization. Replace them if you notice any signs of cracking, wear, or if the O-ring becomes brittle or compressed.

Q: OEM vs. Aftermarket?
A: 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.

Q: How fast do you ship and how much does it cost?
A: 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.

Q: What is your warranty and return policy?
A: 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.