Volvo Penta exhaust leaking water

[mattonthesea]

on a recent trip I noticed that there is water leaking from where the flexible exhaust pipe enters a black box (wide, almost oval shaped pipe - is this a silencer?) The pipe looks a bit sorry for itself around the jubilee clip

Before I delve into the stern locker I thought I should check that cutting a short amount off the pipe and replacing the jubilee clip is ok? Is there anything I should watch out for/inspect while I'm down there?

Thanks in anticipation

 

[VicS]

on a recent trip I noticed that there is water leaking from where the flexible exhaust pipe enters a black box (wide, almost oval shaped pipe - is this a silencer?) The pipe looks a bit sorry for itself around the jubilee clip

Before I delve into the stern locker I thought I should check that cutting a short amount off the pipe and replacing the jubilee clip is ok? Is there anything I should watch out for/inspect while I'm down there?

Thanks in anticipation

That sounds like a silencer but there ought to be a water lock/ water trap as the first thing in the exhaust system after exiting the engine and water injection elbow, The object of the water trap is to safely contain all the water remaining in the exhaust system when the engine is stopped. With a water trap a separate silencer is probably not needed although there should be a swan neck, which may be just a loop of hose , immediately before the final outlet

The On line Vetus catalogue gives some good information regarding exhaust systems
This link will take you to the start of the exhaust section in the catalogue; VETUS Catalogue 2019 - 2020 - English

 

[Spirit (of Glenans)]

Does it look like this VP Silencer (officially called a Waterlock/Muffler) ?
If it is composed a length of large diameter rubber hose, with end gables made of stainless steel, like my one, take it out, seal the inlet end, stand it vertically and fill it with water. If it shows any evidence of leaks it will have rusted through from the inside and have developed pinhole leaks.
Recently, on investigating the origin of unexplained seawater in the bilge I discovered that mine was in this condition.
The boat was re-engined at nine years old, the year before I bought her. She is now twenty years old and I reckon that what I have is the original silencer. If yours is of similar vintage it is a safe assumption that this will be the cause of your problem.
I researched the cost of a replacement from VP; almost €400, replacing it with a plastic Vetus one, ;would not fit in the space, a Centek onein GRP ; the one that would fit in the space did not have enough girth to provide the water capacity required.
I eventually found that Osculati make a replica of the VP one (the part number is made up of the exhaust hose inner diameter in mm plus the overall length plus a zero and another digit between one and nine, e.g. 51.390.05. if you are searching one to replace yours).
Exhaust silencer Ø 51 mm
I found many websites in Italy, France, Spain and Holland displaying them at various prices much lower than the VP original and indeed than the price quoted by Osculati, but most of them were "Non Disponible" (Not Available).
I now have one on order , costing me €302 all in, from a firm in France called Omax Marine Omax Marine Group [contact@omax-marine-group.com] You will have to communicate with them in French.

 

[mattonthesea]

Thanks Vic and Spirit

After looking up all the wet exhaust systems on the web I have just been down to the boat. It doesn't look like any of them! The tubing comes out of the back of the engine, turns under it and does a loop around to the forward end. It then travels to the transom where it rises up and goes into the top end of the muffler/silencer. This is attached to the transom outlet with an elbow (see pictures). There are no other parts to the system.

The verdigris is caused mainly by a leak from the stern hatch but the brown staining is from the exhaust leak. The muffler also appears to have inverted on one side slightly from the leverage of the exhaust tube. Should there be two jubilee clips?

 

[pvb]

Thanks Vic and Spirit

After looking up all the wet exhaust systems on the web I have just been down to the boat. It doesn't look like any of them! The tubing comes out of the back of the engine, turns under it and does a loop around to the forward end. It then travels to the transom where it rises up and goes into the top end of the muffler/silencer. This is attached to the transom outlet with an elbow (see pictures). There are no other parts to the system.

The verdigris is caused mainly by a leak from the stern hatch but the brown staining is from the exhaust leak. The muffler also appears to have inverted on one side slightly from the leverage of the exhaust tube. Should there be two jubilee clips?

I'd be worried that there's not enough watertrap capacity in the system. Maybe time for a serious re-think.

 

[Dipper]

I'd be worried that there's not enough watertrap capacity in the system. Maybe time for a serious re-think.

I agree. Also, if it's leaking water it may also start leaking exhaust fumes.

 

[VicS]

Thanks Vic and Spirit

After looking up all the wet exhaust systems on the web I have just been down to the boat. It doesn't look like any of them!

That looks like an old "Elastomuffle" AFAIK NLA

Do away with it. Replace it with a short length of hose (It'l be a bit noisy but good enough on its own as an emergency get you home measure)

Fit a water trap up near the engine. Follow Vetus advice regarding size. You will probably find that no additional silencer will be needed.

 

[VicS]

That looks like an old "Elastomuffle" AFAIK NLA

Wrong again .... they are still avaialble but I'd still do away with it and fit a water trap ..... In fact we did so decades ago.

 

[mattonthesea]

I think that the installer thought that by having the muffler end up and the exhaust pipe running around and over the engine then the chance of water back tracking is very low; it's got to go up to almost a metre above water line once and then about 500mm the second time.

Anyway, if I take your suggestion Vic can I think of it as the diagram on Vetus p85 for systems below the water line (I have an airvent) but with only the Waterlock Muffler NLP (what does NLP mean?) and just looping the pipe around by the transom to create my own form of gooseneck?

Vetus NLP 40-50 looks like the one to go with a Volvo Penta 2020 on a Rival 32