Exhaust Replacement

Hello, I have a 2005 Mainship Rum Runner, with twin Yanmars. My exhaust is showing signs of wear, has anyone done this type of maintenance? There is very little room where the mufflers are. Any suggestions, this forum is always a place for sound advice.

Greetings,
Mr./Ms. 143. IF you're not going to DIY, get in touch with De'Angelo exhaust in Ft. Lauderdale. Good bunch to work with and a LOT of in house knowledge.
DeAngelo Marine Exhaust Systems | Diesel Soot Filtration

What part of your exhaust system is showing signs of wear? The risers and mixer (spray ring) are metal fabrications while the fiberglass components are off the shelf.

As you mention the mufflers Centek Centek Industries - wet exhaust systems, genset pollution control makes fiberglass mufflers and may have even supplied to Mainship as OEM. The other potential muffler supplier to Mainship would have been Ultra Marine in Maryville Georgia. As you say you have evry little space a direct replacement may be your best fit if it's the muffler you are looking to replace.

DeAngelo Marine makes risers and mixers and purchases fiberglass components from Centek.

Some good reading up on riser and exhaust systems.
Designing a Marine Exhaust System - Seaboard Marine

I have the same boat, but with the single Yanmar. The original geometry of the dry riser and the mixer was bad: not enough clearance above the water line and the mixer was not self draining. I fixed both of these problems by adding an 8" extension to the dry riser.

Your engines probably have a similar Yanmar dry elbow followed by Yanmar's mixer and have the same deficiencies. But most Pilot 34 owners report no problems with that geometry. I modified mine for peace of mind.

So, at the very least I would replace the mixers if they show any signs of internal corrosion. That will avoid a catastrophe if they start to leak back into the engine. But take a look at the throat of the exhaust turbo when you have it apart. Any significant signs of rust or corrosion is a sure indication that sea water is getting back there.

See the attached pic of a non self draining mixer- see the water level left inside and Tony Athens exhaust height criterion.

David

Keysdisease, it's the 4 inch exhaust hour that's showing the wear. Space where the mufflers are is very tight. I'm a DIY person, but having second thoughts.

Huh?

Cyn143srog said:

it's the 4 inch exhaust hour that's showing the wear.

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Hose? Easy replacement, just shop for marine exhaust rated hose. I personally do not like the wire reinforced hose for exhaust, for what that's worth.

Greetings,
Mr. K. What alternative is there to the wire reinforced hose? Silicone?

RT Firefly said:

Greetings,
Mr. K. What alternative is there to the wire reinforced hose? Silicone?

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Here you go. . . .

Greetings.
Mr. LM. Thanks. As I suspected but I was completely unaware of the construction of silicone hoses.

All the major marine hose suppliers offer a rubber exhaust rated hose with no wire. Shields series 200 for instance is Lloyds type approved. Silicone works too, but you don't have to step up to silicone for no-wire exhaust hose.

SeaStar Solutions

In my experience the wire rusts, expands due to rusting (even if its stainless) and then punctures the inside laminates of rubber. This just accelerates deterioration and shortens life.

Wire reinforced hose has its place, on intakes where collapsing might occur, but hot and corrosive exhaust gases mixed with hot salt water just play hell on metal that doesn't need to be there. If it needs to be there to keep the hose from kinking in a bend that is unavoidable, then it has to be there.

RT Firefly said:

Greetings,
Mr. K. What alternative is there to the wire reinforced hose? Silicone?

Click to expand...

Keysdisease said:

All the major marine hose suppliers offer a rubber exhaust rated hose with no wire. Shields series 200 for instance is Lloyds type approved. Silicone works too, but you don't have to step up to silicone for no-wire exhaust hose.

SeaStar Solutions

In my experience the wire rusts, expands due to rusting (even if its stainless) and then punctures the inside laminates of rubber. This just accelerates deterioration and shortens life.

Wire reinforced hose has its place, on intakes where collapsing might occur, but hot and corrosive exhaust gases mixed with hot salt water just play hell on metal that doesn't need to be there. If it needs to be there to keep the hose from kinking in a bend that is unavoidable, then it has to be there.

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As they say, YMMV but wire reinforced exhaust hose has been around a long, long time and the problems you discribe are few and far between from what I've seen. And even when I've seen them, the hose is very old.

Capt.Bill11 said:

As they say, YMMV but wire reinforced exhaust hose has been around a long, long time and the problems you discribe are few and far between from what I've seen. And even when I've seen them, the hose is very old.

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My point was that if it doesn't need to be there, why have it? It cost's more, and I have seen it cause failure.

So unless there's a bend that might kink without the wire in the hose, there is no reason to pay more for something that may not last as long as a less expensive version?

Replaced the exhaust hose, my concern was water coming in through muffler. I placed a bag over exhaust outlet just to be safe. It was an easy fix. Thank You for all your input.

A correctly sized and inflated to fit fender makes an excellent exhaust plug, even has a place for a line to attach, looks better than a bag too I'll bet

Cyn143srog said:

Replaced the exhaust hose, my concern was water coming in through muffler. I placed a bag over exhaust outlet just to be safe. It was an easy fix. Thank You for all your input.

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