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SIERRA
Exhaust Flapper Valves

Heavy duty rubber flapper valve keeps following seas from entering exhaust outlet when moving slowly or stopping.
  • Includes adjustable stainless-steel clamp
Product Models
Description WM Model # MFG Part # Availability Price Quantity  
Exhaust Flapper Valve - 3" 394181 18-4456D
In stock online.

$29.99

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Exhaust Flapper Valve - 4" 402695 18-4457D
In stock online.

$30.99

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Exhaust Flapper Valve - 5" or 6" 361966 18-4458D
In stock online.

$49.99

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Heavy duty rubber flapper valve keeps following seas from entering exhaust outlet when moving slowly or stopping.
  • Includes adjustable stainless-steel clamp

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REVIEW SNAPSHOT®

by PowerReviews
SierraExhaust Flapper Valves
 
4.0

(based on 3 reviews)

Ratings Distribution

  • 5 Stars

     

    (2)

  • 4 Stars

     

    (0)

  • 3 Stars

     

    (0)

  • 2 Stars

     

    (1)

  • 1 Stars

     

    (0)

67%

of respondents would recommend this to a friend.

Pros

  • Good performance (3)

Cons

No Cons

Best Uses

No Best Uses
    • Reviewer Profile:
    • Advanced (3)

Reviewed by 3 customers

Displaying reviews 1-3

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5.0

A simple device but so important!

By RUSH CASE

from Chicago

About Me Advanced

Verified Buyer

Pros

  • Good Performance
  • Reliable
  • Weather Resistant

Cons

  • Noisy

Best Uses

  • Large Boats
  • Small Boats

Comments about Exhaust Flapper Valves:

Check exhaust flappers seasonally for fatigue, cracks. One of mine failed and water backed up the exhaust and entered the cylinder head and invaded the oil! Engine did not want to crank or start. Thankfully no permanent damage was detected! I replaced both flappers. Changed oil and filter and I'm up and running!!

  • Was this a gift?:
  • No
 
5.0

Reassuring to see the exhaust closed

By Motorboat GRACE

from Gilmerton Canal, Virginia

About Me Advanced

Verified Buyer

Pros

  • Good Performance
  • Reliable
  • Weather Resistant

Cons

    Best Uses

      Comments about Exhaust Flapper Valves:

      Replasced at five-year intervals while still functioning perfectly

      (2 of 2 customers found this review helpful)

       
      2.0

      I won't buy this size again.

      By Boater

      from Mobile, AL

      About Me Advanced

      Verified Buyer

      Pros

      • Good Performance

      Cons

      • Poor Design

      Best Uses

        Comments about Exhaust Flapper Valves:

        You can only order it to fit a 5 and 6 inch exhaust but it doesn't work well on the 5 inch exhaust. It distorts when clamped down to fit the 5 inch exhaust. I will use it until I can find one made for a 5 inch exhaust and then replace it.

        Displaying reviews 1-3

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