SKU: 77279717084

Exhaust Flapper Valve & Clamp Kit – Fits 5" & 6" OD Exhaust Pipes (Replaces Sierra 18-4458, GLM 89260, Mallory 9-44002)

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Description

Exhaust Flapper Valve & Clamp Kit – Fits 5" & 6" OD Exhaust Pipes (Replaces Sierra 18-4458, GLM 89260, Mallory 9-44002)Exhaust Flapper Valve & Clamp Kit Fits 5" & 6" OD Exhaust Pipes This marine exhaust flapper valve kit is designed to prevent water from rushing in through exhaust thru hulls when your boat is stopping, moving at slow speeds, or backing up. It is a crucial component for protecting your engine from water ingestion and potential damage. This kit is suitable for a wide range of inboard and stern drive applications with 5 inch or 6 inch outside diameter

Exhaust Flapper Valve & Clamp Kit – Fits 5" & 6" OD Exhaust Pipes

This marine exhaust flapper valve kit is designed to prevent water from rushing in through exhaust thru-hulls when your boat is stopping, moving at slow speeds, or backing up. It is a crucial component for protecting your engine from water ingestion and potential damage. This kit is suitable for a wide range of inboard and stern drive applications with 5-inch or 6-inch outside diameter (OD) exhaust pipes.

This universal kit is a direct replacement for several common part numbers, ensuring broad compatibility with many popular engine setups. Please note that installation on a 5-inch pipe requires modification.

  • Fits: 5" and 6" (127mm & 152.4mm) Outside Diameter Exhaust Pipes
  • Material: Durable EPDM rubber with UV stabilizer and a marine-grade SS316 stainless steel clamp
  • Package Includes: Two exhaust flapper valves and two stainless steel clamps

Part Number Cross-Reference

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

Brand Part Number
Sierra 18-4458
GLM 89260
Mallory 9-44002

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.

Brand Model Rated HP Stroke Notes
Chris-Craft Inboard Engines Various 4-Stroke For 5" & 6" exhaust pipes
Chrysler Inboards Various 4-Stroke For 5" & 6" exhaust pipes
Crusader Inboards Various 4-Stroke For 5" & 6" exhaust pipes
Mercury/Mariner Inboard/Outboard Various 4-Stroke For 5" & 6" exhaust pipes
Pleasurecraft (PCM) Waukesha Various 4-Stroke For 5" & 6" exhaust pipes

Technical Specifications

Specification Value
Product Type Exhaust Guard / Flapper Valve & Clamp Kit
Installation External; 5" requires two 45° cuts
Connection Clamp-on to exhaust pipe
Housing Material Weather resistant EPDM rubber with UV stabilizer
Housing Color Black
Dimensions Fits 5" & 6" OD pipes (127mm & 152.4mm)
Fitting Type Stainless steel hose clamp
Other Technical Attributes Stainless steel clamp is marine grade SS316
Warranty 1 Year (YiheoZux brand) or Limited Lifetime (Sierra brand)

Package Contents

  • 2 x Exhaust Guard Covers
  • 2 x Stainless Steel Hose Clamps

Installation Guide

Follow these steps to install the exhaust flapper valve:

  1. Ensure the engine is off and the exhaust system is cool to the touch.
  2. For 6-inch pipes, slide the flapper valve directly over the exhaust pipe outlet.
  3. For 5-inch pipes, you must first make two 45-degree cuts into the rubber housing to allow it to fit snugly.
  4. Position the flapper so the valve opens away from the transom, allowing exhaust gases to exit freely.
  5. Place the stainless steel clamp over the rubber housing where it meets the pipe.
  6. Tighten the clamp securely with a screwdriver or socket wrench until the flapper is held firmly in place. Do not overtighten, as this could damage the rubber.
  7. Visually inspect the installation to ensure a secure fit and correct orientation.

Troubleshooting & FAQ

How do I know if this flapper kit will fit my exhaust?

This kit is designed for exhaust pipes with a 5-inch or 6-inch outside diameter (OD). Measure the outer edge of your exhaust pipe to confirm the size. It is a universal fit for many inboard and I/O brands like Mercury, Chris-Craft, and Crusader using these pipe sizes.

What is the purpose of an exhaust flapper?

The flapper acts as a one-way valve on your exhaust outlet. It prevents water from surging back up the exhaust pipe when you are backing up, stopping suddenly, or in rough seas, which protects the engine from water damage.

My exhaust pipe is 5 inches. How do I modify the flapper to fit?

To fit a 5-inch OD pipe, you must make two 45-degree angle cuts into the rubber housing. This allows the rubber to slightly overlap and clamp down to the smaller pipe diameter for a secure seal.

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.
Shipping Notes
  • Free Standard Shipping on $100+ Orders to the USA.
  • Except Preorder products are shipped in 48 hours.
  • Delivery to the USA:
  1. Standard Shipping : 3-10 business days
  • If time is of the essence, please consider selecting expedited delivery for faster service.
Exchange/Return Notes
  • We offer a 30-day return/exchange service after receiving.
  • Final sale items are not eligible for returns or exchanges.
  • To process your return/exchange, please contact us at [email protected]
  • Please click here for more details>>> Return & Exchange Policy
SKU: 77279717084

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4.6 ★★★★★
Based on 11 reviews
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Product Reviews
C
Verified Purchase
Chay
Natrona Heights, US
★★★★★ 5
Great for Tough chewers!
Size: Large, Color: Dinos Frills (Red)
My dog is a tough chewer and absolutely loves this toy! He was able to get a little stuffing out of the leg so far and it’s been about a week. This might sound like a short amount of time but it usually takes him under 15 mins to unstuff a large toy even if they are advertised for “tough chewers!” This is a very large size toy and would be good for any larger breed. He carries it around the house and constantly keeps his Dino with him. Since Ive found GoDog toys I’ve only been purchasing them because of their durability. I’ve tried Kong and Bark toys previously and they just do hold up long and are usually more expensive. This toy is a great value and dogs love them!
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on October 20, 2025
G
Verified Purchase
Gerry
Waukegan, US
★★★★★ 5
Super cool strong dog toy!
Size: Large, Color: Dinos Frills (Red)
Super cool strong dog toy!
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on May 12, 2026
M
Verified Purchase
MalinoisLover
Los Angeles, US
★★★★★ 4
LOVE this brand. Have many of their styles. This is basically an unstuffed toy.
Size: Large, Color: Dinos Frills (Gray)
I have about 10 -12 different styles of the GoDog brand toys. It is like Xmas when my Malinois dogs get a new GoDog toy. Have loved this brand for many years and have some toys which have lasted 5-6 years -- minor "surgeries" stitch they back together -- until I retired them. They have never just worn out. Just to be clear: THESE TOYS ARE NOT CHEW PROOF. NO STUFFED TOY IS CHEW PROOF. However, this brand of stuffed toy is more chew proof than other brands. But if you are looking for a chew proof stuffed toy be advised -- IT DOES NOT EXIST!! No fabric is chew proof. Even if they invented such a fabric I would not want to ruin my dog's teeth by letting them try to chew through it. Protecting one's dog's teeth should be the highest priority. If a dog can chew through a PLASTIC KENNEL and even METAL WIRE KENNELS (yes, it happens) then they can easily chew through a puffy, fluffy stuffed toy. The "Chew Guard Technology" language may be misleading to some customers who are disappointed in the brand. I defend the brand and have used it for many years. No, I don't get paid or get free toys. Since I have had many styles within this brand and even have the pink version of this style I thought I knew what I was getting. This is basically a toy without stuffing which some people prefer. For whatever reasons my dogs prefer toys that are stuffed. Really stuffed with a firm density that they can sink their teeth into. So this toy will be OK. I can tell it will not be one of their beloved toys like some of the brand's other styles such as the purple brontosaurus. My fault for not reading more closely and assuming the grey version would be exactly like the pink version which is fully stuffed. If they get bored with these two I keep some of the Chew Guard toys stock piled. BTW one can wash and dry these toys. Yes, eventually the squeakers suck up some water and die but one can replace the squeakers. Also on Amazon. So I am willing to replace the squeakers a few times in the life time of one of these toys to be able to wash and dry them occasionally. Usually takes a couple drying cycles to get the heavily stuffed toys dried completely. If you have an aggressive chewer you may wish to look into Goughnuts dog toys or other hard rubber toys that are designed for aggressive chewers. Even then, with a determined dog, the Goughnuts toys can be chewed through. I think they offer a replacement guarantee. The other brand which has some toys of hard rubber is West Paw. An excellent brand that also offers a one time replacement. Bully Sticks are another option for chewers. PLEASE, PLEASE, PLEASE stay away from the hard plastic chew toys like the Nyla Bones. Hard plastic toys will destroy your dog's teeth over time. I learned the hard way (no pun intended) and ruined one of my dog's teeth. Vet asked if I allowed my dog to chew ROCKS !!!!!! Every tooth was cracked or fractured. Not wishing to pull teeth I had to pay for some very expensive root canals and caps. Vet's advise: If you can't dent the toy or chew with your finger nail DO NOT offer to your dog. Good advise to follow. Even some of the Bully Sticks (Costco Brand) are so hard they can chip or fracture teeth. Best for you and your dog.
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Reviewed in the United States on September 1, 2019
P
Verified Purchase
P SD
West Palm Beach, US
★★★★★ 5
Well made, minor issue was quickly resolved
Size: Large, Color: Dinos Bruto (Purple)
I purchased the Dino Bruto Dog toy for my labradoodle who is quite fond of squeaky, squawky stuffed toys and oddly enough has shown a preference for purple. I opened the package with my hound standing by waiting for his gift. I detached the tags and attempted to squeak the toy. It seemed difficult to squeak or honk. I tossed the purple Dino Bruto to my dog who excitedly chomped to squeak. The toy squawked a couple times and then just quit. My poor hound was staring up at me with that "what's up with this" look on his face. I tracked down the website for the GoDog toys, not going through the Amazon return process. I called the good people at GoDog and stated simply that my dog's favorite part of the toy failed quite quickly and I was wondering about guarantees. I was told to go to the website and file a replacement request. The replacement request required that I include a photo which I did as directed. I received an reply email within a couple hours which stated that a new toy would be sent out shortly. I am happy to report that we received a replacement toy, not the purple Dino, but a colorful wood duck. The squawker device works well and is still performing like new more than a month later. It appears that the squeaker is not those little plastic squeakers but the bigger heavy plastic bag, bladder, with what I visualize as a duck call sort of sound device. I am guessing because I haven't seen the inside of the GoDog toys. I have seen the guts of other stuffed toys which use this type of noise device. While our dog seems to enjoy the sound of the plastic bag, bladder set-up squawkers, they seem to fail quickly and I tend to avoid them because of this. The toys using this type of squawker that I have seen, use what looks like a cheap lightweight plastic bag which is not securely attached to the "voice box". Since the GoDog replacement toy is holding up so well, I am guessing GoDog uses a heavier grade plastic bladder coupled with reinforced construction. The purple Dino Bruto toy still looks new even after multiple times of our hound grabbing the purple toy, shaking it at us with his invite to give chase or play keep away. Since the squawker failed so quickly with the new toy, I figure it was just a defective item which does not reflect the general quality of toys from GoDog. One evening our neighbor was visiting while his pitbull was playing in our yard with our dog. Our patio door was open so our dog ran into the house and grabbed his purple Dino Bruto toy. He is a bit of a show-off with new toys. Our dog then went racing back into the yard, shaking his GoDog toy at the pitbull. A quick game of tug-of-war ensued. Since this is a new toy, our neighbor leaped into the game and took the toy away from the dogs. In that short time of tugging between the dogs, the toy held together and did not even pull apart at any of the seams. There were no puncture marks either. This is a game our dog has initiated before with the neighbor pitbull. Normally, the stuffed toys are ripped apart almost immediately. I was surprised and impressed with the quality of the sewing which appears to employ some sort of reinforced construction or heavier material. I plan to make more purchases from GoDog toys. The toys are a little more expensive than some stuffed dogs toys but they hold up so well I figure they are worth a few more dollars. They are great toys that hold up well and the company provides quick responses to inquiries. I consider this a winning combination.
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on June 15, 2013
J
Verified Purchase
Jan F.
Houston, US
★★★★★ 5
Good quality
Size: Large, Color: Dinos Frills (Gray)
we’ve had many godog toys over the years and although my dog eventually rips through them I do find that they last longer than other cheap toys. Overall very well made!
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on May 11, 2026

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