Convert 2" Exhaust hose to 2 3/8" - SailNet Community
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post #1 of 8 Old 08-18-2012 Thread Starter
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Convert 2" Exhaust hose to 2 3/8"


I'm trying to convert my existing engine exhaust hose system from 2" output from the enigine to the 2 3/8" input to the right sized Vetus waterlift muffler. The waterlift is 60mm, darn near 2 3/8". Anyone know of the best right way to do this? I am trying to find a hose connection that goes from 2" to 2 3/8 inch, but can't find one on defender, or from my local West Marine.

The 2"hose fits pretty snug in the 2 3/8 inch and I have a sturdy 2" outside diameter fiberglass coupler from a previous installation that I can use to stiffen the inside of the 2" hose and then tighten the 2 3/8" hose down on. I want to make sure the system doesn't leak because it's going to and from a water lift muffler.

If anyone is interested in the project, I'm blogging about it here: Waterlift Muffler Replacement: Day 1 | Aboard Astraea

Any ideas or part sources, please let me know!



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post #2 of 8 Old 08-19-2012
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Re: Convert 2" Exhaust hose to 2 3/8"

I dont think that changing to a larger size exhaust hose is a good idea, an extra 3/8 dia is a large increase of water volume and a lot more for the exhaust gas to displace. Some here may no more about the physics but the engine was designed by an expert who selected 2" for a reason.


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post #3 of 8 Old 08-19-2012
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Re: Convert 2" Exhaust hose to 2 3/8"

Your solution of fitting one hose on the other is not bad. Another possibility is to use a standard pipe reducer and nipples. 2 inch pipe is actually 2.375" OD and 1 1/2 inch pipe is actually 1.9" OD. Finding them in materials you like might be an issue.
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post #4 of 8 Old 08-19-2012
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Re: Convert 2" Exhaust hose to 2 3/8"

I've seen fiberglass adapters made for marine exhaust systems that are used to connect two different diameter hoses. You might do a search online, or check Fisheries Supply in Seattle (I think that is where I saw them).

Here you go, found them. Scroll down to "reducer couplings".

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Last edited by jrd22; 08-20-2012 at 12:11 AM.
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post #5 of 8 Old 08-19-2012
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You buy the bronze shaft. Ship it to me and and pay to ship it back. Shoot me dimensions you want and I'll turn you some on my lathe.

That size bronze shaft might be found at a yard as a bent prop shaft.

Going to be an expensive piece of metal and much of it will end up as shavings.

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post #6 of 8 Old 08-20-2012
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Re: Convert 2" Exhaust hose to 2 3/8"

On my Cal 28; I used copper sweat plumbing pipe of what ever size I needed and sized up with adapter to go in Plastic muffler . Used hose, double clamped, Works fine! All out of plumbing supply house.....Dale

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post #7 of 8 Old 08-23-2012
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Re: Convert 2" Exhaust hose to 2 3/8"

When I bought my boat, the exhaust outlet from water lift was made of a smaller diameter hose slid into a larger diameter hose with two hose clamps (the od of one hose was the id of the other). Did not leak water or exhaust but I never liked the connection. I found some bronze fittings at west marine and made a hose to hose connection and fitted that. That has worked well. My water lift is two inch outlet and the od of the connected hose was the ID of the 2 inch hose, west marine had these fittings in bronze.

Last edited by casey1999; 08-23-2012 at 01:48 PM.
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post #8 of 8 Old 08-23-2012
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Re: Convert 2" Exhaust hose to 2 3/8"

I would think a 2-1/2 inch fitting would work. buy a 2" pipe to hose fitting and a 2-1/2 inch pipe to hose fitting (bronze) and connect with a 2-1/2 x 2" pipe reducer.

Reducer available here (COUPLING REDUCING BRONZE 2 1/2" X 2" 124510
Item #: MTL-44-462)

As well as the tailpieces (hose nipples):
Item #: GRO-TP-2000
List Price: $60.00 / Each
Your Price: $48.99 / Each


Item #: GRO-TP-2500



Last edited by casey1999; 08-23-2012 at 06:26 PM.
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2 3/8" inch , 2" inch , coupler , water lift muffler

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