Yanmar - high revs water leak

[West Coast]

Hi, I have a 4JH5E coupled to a SD 60 saildrive fitted to a 2012 built jeanneau. The inner GRP moulding which supports the engine and saildrive forms an enclosed box directly under the engine, the box is deep and has no drain holes or similar.

When running at 2000 to 2200 rpm, all is fine, and the box stays completely dry. When running at 2400 rpm, the box fills with seawater from somewhere, clear seawater ( no sooty deposits). For instance, a 2400 rpm run for approx 3 hours last week resulted in a bucket full of water. This issue is independent of sea conditions, rough or smooth. I cannot see any way how the water could get there from elsewhere since the surrounding GRP areas are dry, it can only becoming from the engine. But any ideas where from on the engine, and why it is only happening at higher revs?

I bought the boat a couple of years ago, this problem has existed since I have bought her.

Thoughts welcome! Thanks

 

[RichardS]

It might well be coming from the seawater pump which is allowing some seawater past the seals at higher revs. It will be dripping down probably from a tell-tale hole.

Richard

 

[Caladh]

Anti siphon device drain ?

 

[West Coast]

Thanks, both good ideas - the added pressure from the higher revs could be resulting in seawater pushing past seals which are ok normally?

 

[scottie]

Check your hose around the connection points especially where hose clips are not
I would think it’s getting too much not to sort out before it gets worse at an inconvenience time

 

[West Coast]

Scottie - agreed, but it has been hard to track down. The issue is intermittent and it is only as I have been recording the incidents and circumstances that it has become clearer it it seems somehow linked to engine revs. Checking round the engine, the hoses all seem ok, and as said, long running (8 hours +) at moderate revs , there is no sign of any water, or even any salt residue (ie if a small saltwater leak was happening and with engine heat evaporating the water, it would leave salt residue, but this is not the case).

 

[LittleSister]

Could it perhaps not be coming from the engine, but from below: a leak of the sail-drive/hull gasket (?) when under higher loads and/or greater vibration? (I have no practical knowledge of these things - just speculating.)

 

[West Coast]

Could it perhaps not be coming from the engine, but from below: a leak of the sail-drive/hull gasket (?) when under higher loads and/or greater vibration? (I have no practical knowledge of these things - just speculating.)

Thanks for the idea - this was something I wondered at the beginning but I don't think so as there would then be water in some of the surrounding areas, which there is not.

 

[scottie]

Could it perhaps not be coming from the engine, but from below: a leak of the sail-drive/hull gasket (?) when under higher loads and/or greater vibration? (I have no practical knowledge of these things - just speculating.)

Yanmar has a double layer gaiter with water sensor in between

 

[Homer J]

I had this on my jeanneau / yanmar and it came from the water pump seal. The plate was quite worn by the impeller.