Exhaust Protector Valve – Fits Chris-Craft, Chrysler, Crusader, PCM & Mercury/Mariner 5" & 6" (Replaces 18-4458, Mallory 9-44002, Mercury 700-834800A5)

Exhaust Protector Valve – Fits Chris-Craft, Chrysler, Crusader, PCM & Mercury/Mariner 5" & 6"

This external-mount exhaust protector valve is designed for a wide range of inboard and outboard marine engines with 5-inch or 6-inch exhaust outlets. Its primary function is to prevent water from entering the engine through the exhaust system, a critical safety feature for engine longevity and performance.

Manufactured from durable, weather-resistant EPDM rubber with a UV stabilizer, this valve assembly withstands harsh marine environments. It is a direct replacement for GLM 89260, Mallory 9-44002, and Mercury 700-834800A5, ensuring broad compatibility and reliable performance.

• Installation Method: Installs externally on the exhaust tip with a simple clamp-on attachment.
• Engine Compatibility: Fits various models from Chris-Craft, Chrysler, Crusader, Pleasurecraft (PCM), and Mercury/Mariner.
• Important Fitment Note: Installation on a 5-inch exhaust requires two 45° cuts on the valve for a proper fit.

Part Number Cross-Reference

Use this table to confirm equivalent part numbers across OEM andbrands.

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.

Confirm your engine model/year in the table below.

Chris-Craft Inboard

Chrysler Inboard

Crusader Inboard

Pleasurecraft (PCM) Waukesha

Mercury/Mariner

Technical Specifications

Package Contents

• 1 x EPDM Rubber Flapper Valve (Replaces 18-4458)
• 1 x Stainless Steel Clamp (Included with valve assembly)

Installation Guide

1. Ensure the engine is turned off and the exhaust system is cool to the touch.
2. For 5-inch exhaust outlets only: Carefully make two 45° cuts on the rubber flapper valve as needed to ensure a snug fit. This step is not required for 6-inch outlets.
3. Slide the EPDM rubber flapper valve over the end of the exhaust tip.
4. Orient the valve so the flapper hangs downward, allowing it to open with exhaust pressure and close to prevent water entry.
5. Position the stainless steel clamp over the mounting area of the valve.
6. Tighten the clamp securely with a suitable tool until the valve is firmly attached to the exhaust tip.
7. Gently check that the flapper can move freely without binding or obstruction.

Troubleshooting & FAQ

How do I confirm this fits my engine?
This protector valve is designed for marine engines with 5-inch or 6-inch diameter exhaust outlets. It's compatible with models from Chris-Craft, Chrysler, Crusader, PCM, and Mercury/Mariner. The best way to ensure fitment is to measure your exhaust tip and cross-reference the part numbers (GLM 89260, Mallory 9-44002, Mercury 700-834800A5) with your existing part.

Do I need to modify this valve for it to fit?
For 6-inch exhaust systems, the valve should fit directly without modification. However, if you have a 5-inch exhaust outlet, you must make two 45° cuts on the rubber housing to adapt it for a proper seal.

What are the signs that my old exhaust flapper needs replacing?
Inspect your existing flapper for signs of wear such as cracks, brittleness, stiffness, or warping. A compromised flapper will not create an effective seal, increasing the risk of water flowing backward into the engine (water reversion), which can cause catastrophic engine damage.

OEM vs. Aftermarket?
This listing is anreplacement 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 anreplacement 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.