Valve on waterlift muffler

[Cyrus Safdari]

I'm considering placing a drain tube and shutoff valve on my normally- inaccessible Vetus waterlock muffler. The cap and drain point towards aft far under my fuel tank, unreachable normally

As everyone knows one of the big issues with these mufflers is that the capacity of the water in the exhaust hose which doesn't make it past the gooseneck and falls back down into the waterlift muffer, will exceed its holding capacity or volume, causing water to back up into the engine cylinders causing waterlock

So why not use a compressor valve? When the engine is on and the waterlift muffler is pressurized, the valve closes closes. Once the engine is off, the pressure falls and the valve opens to drain the muffler

[Uncle Bob]

Originally Posted by Cyrus Safdari

I'm considering placing a drain tube and shutoff valve on my normally- inaccessible Vetus waterlock muffler. The cap and drain point towards aft far under my fuel tank, unreachable normally

As everyone knows one of the big issues with these mufflers is that the capacity of the water in the exhaust hose which doesn't make it past the gooseneck and falls back down into the waterlift muffer, will exceed its holding capacity or volume, causing water to back up into the engine cylinders causing waterlock

So why not use a compressor valve? When the engine is on and the waterlift muffler is pressurized, the valve closes closes. Once the engine is off, the pressure falls and the valve opens to drain the muffler

Out of curiosity do you know anyone that has encountered this problem with Vetus mufflers or you just worried about something that you perceive to be a problem?

[cal40john]

You have the wrong size Vetus if that is a problem.

From Vetus:
https://webshop.vetus.com/en/product...-installations

Waterlocks, standard installations
Once the engine of your boat has stopped, a VETUS waterlock of the correctly chosen capacity will make sure that water will not backflow into the engine. All VETUS waterlocks are provided with a drain plug for winter storage.

[noelex 77]

Originally Posted by Cyrus Safdari

As everyone knows one of the big issues with these mufflers is that the capacity of the water in the exhaust hose which doesn't make it past the gooseneck and falls back down into the waterlift muffer, will exceed its holding capacity or volume, causing water to back up into the engine cylinders causing waterlock

The system should be designed and sized so this will not happen.

The exception is with a defective engine that will turn over, but not start. The impeller pumps water as the engine is cranked, but there is no exhaust pressure to push the water out. The waterlock can fill. The usual solution, if the engine will not fire normally for some reason, is to turn off the raw water inlet until the engine starts.

The drain on the waterlock should be accessible, but this is generally only used for winterising the system.

[Locquatious]

After Irma, our boat lay 55 degrees over in the yard. It appears the residual water in the waterlift muffler may have been tipped into our generator, leading to later engine failure.

While that is an extreme and rare situation, a boat heeled-over hard may lift the muffler, relative to the engine, such that water can splash in.

We too have wondered if it would be better to allow the waterlift muffler to drain after use.

[ItDepends]

Originally Posted by Cyrus Safdari

As everyone knows one of the big issues with these mufflers is that the capacity of the water in the exhaust hose which doesn't make it past the gooseneck and falls back down into the waterlift muffer, will exceed its holding capacity or volume, causing water to back up into the engine cylinders causing waterlock

Nonsense. A properly designed exhaust system will not do this. There are a lot of ways to get water into a boat’s engine, and almost all of them are the result of poor system design or installation.

Exhaust system design requires a lot of interacting details to be done right. Shortcuts are common by mechanics, boat builders, and boat owners. Those shortcuts will (sooner or later) spell disaster for the engine.

[ggray]

Originally Posted by noelex 77

The system should be designed and sized so this will not happen.

The exception is with a defective engine that will turn over, but not start. The impeller pumps water as the engine is cranked, but there is no exhaust pressure to push the water out. The waterlock can fill. The usual solution, if the engine will not fire normally for some reason, is to turn off the raw water inlet until the engine starts.

The drain on the waterlock should be accessible, but this is generally only used for winterising the system.

Yes, but if you turn off the raw water inlet, don't you run the risk of damaging the impeller while cranking the engine?

[goboatingnow]

No not during cranking

[Bowdrie]

I have one of those "Vernalift" mufflers and installed a drain hose that leads a few inches to a mounted ball valve with easy/quick access.
When the engine isn't being used, open the valve.
It's not rocket science and the muffler stays dry, with no water vapor to rise back into the manifold.
The Vernalift, being filiment wound fiberglass is easily worked with, a molded plastic Vetus?, now that might prove more difficult.
I'm not sure that even G-Flex epoxy will make a strong/reliable bond on the plastic that Vetus uses.

[Lepke]

I have water lift mufflers on 2 Detroits and 2 generators, no idea what brand or age.


I use compressor dump valves without issue. Having the mufflers empty makes for easier starting.

[double u]

connected the drain of the water-lock to the valve-battery (for draining different bilge-compartments) of the bilge pump. Whenever the engine was stopped & the intention was to not run it again the same day: openvalve, run bilgepump for 1min, shut valve.