Water leak after new engine installation

[Graham028]

Hi. I have just fitted a new Nanni 21hp engine to my 30 year old Beneteau First 345. On the two occasions I have used the engine in rough conditions large amounts of water have appeared in the bilges. I have checked the engine pipe work and seacocks but can find no leaks. The problem does not occur when sailing. Can anyone suggest where this water is coming from ?


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[sailfish2008]

check your stern gland

[Graham028]

The stern gland seems fine- renewed last year. I'm wondering about the exhaust system as this engine sits a bit lower than the previous Volvo 2002. Could it be syphoning ? The engine runs perfectly and how could the water get into the bilges in such large quantities- several gallons.


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[DougR]

Only happens when motoring in rough conditions........?

- softer flex mounts allowing misalignment at the stern gland thus leaking?
- leaking anti-siphon valve? ( should happen all the time)
- loose strut (p bracket)?
- loose keel bolts?
- small crack in water lift muffler which flexes open in rough conditions?
- loose exhaust hose connection at thru-hull outlet?

Time to get a helper crawling thru the boat when motoring....

DougR

[jkishel]

Doesn't sound like an exhaust issue as a leaking anti siphon or hose would probably leak in calm or rough conditions with the engine running.

Check the rudder post packing gland. This can be under water when motoring but not under sail. Also check all above water line through hulls; shower drain, head sink drain, etc. These can be under water when under way.

Also check the bilge pump system. If the through hull is too low it can be under water in certain conditions providing a direct path for sea water to enter the bilge.


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[Graham028]

Thanks to DougR and jkishel for some real good suggestions. Now looking for a small flexible bilge crawler !!


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[svHyLyte]

Originally Posted by Graham028

Hi. I have just fitted a new Nanni 21hp engine to my 30 year old Beneteau First 345. On the two occasions I have used the engine in rough conditions large amounts of water have appeared in the bilges. I have checked the engine pipe work and seacocks but can find no leaks. The problem does not occur when sailing. Can anyone suggest where this water is coming from ?


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Carefully examine the connection between the exhaust hose and the water-lift muffler. You may find that the connection isn't tight, particularly if the hose hasn't been replaced. Also check the exhaust hose between the muffler and the discharge port in the transom. If it is the original, you may well find a crack that opens when the hose flexes around. We had a similar issue with an original exhaust hose that proved to be cracked roughly 2" from the point where it was clamped to the exhust thru-hull fitting. I could have just chopped off the broken end but the hose was so old and inflexible I chose to replace it. Worming it through the bilge from the muffler to the transom was a heck of a job only made endurable by the Vetus hose that was much more flexible than the original.

Good Luck!

[Cheechako]

I like the rudder post packing gland idea. Had that happen once. The boat squatted when motoring and the water flowed like a stream down to the bilge. But yes, check the packing gland while motoring.

[jkishel]

To check above water through hills and connected piping, aim a hose at each through hull and check for water intrusion.


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[DeepFrz]

Sometimes the water lift mufflers have drain cocks. Maybe you have one and its open?

[Scrimshaw4]

Rough conditions may be causing additional pressure at the RW intake side, between the TH and RW pump. If any of these connections are not thiroughly tight, double hose clamped, water may be leaking there. Over pressure may alos be making it's way to the heat exchanger.

[kelbylinn]

Raw water pump? Only leaks when engine is running and warm ifthere is a bad seal.

[Graham028]

Hi All. Found the leak!! The muffler had a copper fitting with a blanked off hose attached. This fitting had corroded and there was a small hole on the underside just before the hose attachment. This was leaking downwards on the starboard side but the water was emerging on the port side at the galley having tracked under the engine tray. One disadvantage of the Beneteau internal mouldings. The muffler was also connected the wrong way round but I'm not sure if this was significant. Anyway a new muffler is on the way which will solve the problem. Thanks to everyone who posted suggestions. This forum is a really valuable valuable resource.


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[svHyLyte]

Originally Posted by Graham028

Hi All. Found the leak!! The muffler had a copper fitting with a blanked off hose attached. This fitting had corroded and there was a small hole on the underside just before the hose attachment. This was leaking downwards on the starboard side but the water was emerging on the port side at the galley having tracked under the engine tray. One disadvantage of the Beneteau internal mouldings. The muffler was also connected the wrong way round but I'm not sure if this was significant. Anyway a new muffler is on the way which will solve the problem. Thanks to everyone who posted suggestions. This forum is a really valuable valuable resource.

Good for you. All's well that ends well.