Find me this engine anti-siphon

[Pye_End]

It doesn't look as if it has a non-return valve and just piddles out water from the restricted outlet when the engine is running. That's just a guess and I'm dubious about how well it works as a syphon break. I assume the actual vent pipe is the larger one at the top and that breaks the syphon but don't think OP confirmed that fact.

Looks the same as mine, except the extra connection. Valve accessible by taking one or both nuts off. Vent tube on the top / right just there to direct any overspill - eg bit of salt build up that doesn't allow valve to fully seat. Works fine as a valved syphon break.

 

[alan_d]

It is just a three- (or four-) way tee, whatever way you look at it.

Wouldn't a four-way T be an H?

 

[VicS]

Looks the same as mine, except the extra connection. Valve accessible by taking one or both nuts off. Vent tube on the top / right just there to direct any overspill - eg bit of salt build up that doesn't allow valve to fully seat. Works fine as a valved syphon break.

A repair kit is available from Keypart for £6.50 > > > > a lot less than buying a modern one and adding a T piece for the stern gland feed


See:- https://keypart.blob.core.windows.net/stock/images/875738-Rv1.jpg

.

 

[scottie]

A repair kit is available from Keypart for £6.50 > > > > a lot less than buying a modern one and adding a T piece for the stern gland feed


View attachment 148384See:- https://keypart.blob.core.windows.net/stock/images/875738-Rv1.jpg

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Just had another look don’t bother there is no valve involved now

 

[Bilgediver]

The OP said:


I think that was probably read as it feeding the stern tube rather than just being a piddle tube where water can be seen exiting.

I this pipe does run to the shaft housing then it may not work as an antisyphon device. Let-s see what the OP tells us about that pipe.

 

[Mistroma]

Looks the same as mine, except the extra connection. Valve accessible by taking one or both nuts off. Vent tube on the top / right just there to direct any overspill - eg bit of salt build up that doesn't allow valve to fully seat. Works fine as a valved syphon break.

The extra connection made think there could be alternatives I hadn't considered. I thought the the extra connection would either just be a vent or go to the exhaust elbow. The line to the elbow should drain when the engine stops, allowing entry of air to break the syphon.

I wondered if there might be room for a small valve but it looked quite small. Good to know that it does have non-return valve and that does indicate it is meant to be where air would enter to break any syphon. Does your pipe to the stern tube? That's the bit that was puzzling me because it means it would be connected to something always under water.

My current boat has clear hoses and it's easy to check that the syphon is being broken. It would be good if your boat also has clear hoses to check operation, especially if it connects to the stern tube.

I this pipe does run to the shaft housing then it may not work as an antisyphon device. Let-s see what the OP tells us about that pipe.

Yes, more detail required in order to determine how it is connected and whether it is even meant to be an ant-syphon device or something else. My old Southerly was designed to run in shallow water with the prop. close to a sandy or muddy bottom. There was a T-piece feeding water to the Cutless bearing instead of the more normal external side intakes. Water to the bearing came from slightly higher, well away from the prop. and through a sediment trap. I doubt OP's boat needs anything similar but you never know.