DeeGee
Well-Known Member
Anyone know what this is...and how exactly it works. It is on my boat, sealed and taken for granted till yesterday......
NOT A QUIZ:
- Thread starter DeeGee
- Start date
StugeronSteve
Well-Known Member
Looks a little like an anti syphon arrangement.
This is not a quiz entry!
This is not a quiz entry!
jrt
Well-Known Member
It looks like an anti-syphon device. If it is connected into the cooling water line then there is a fair chance that I am right. I take it that the top pipe just goes to the outside of the boat.
There are more experienced people than me on this forum and they may be able to give you a definitive answer.
There are more experienced people than me on this forum and they may be able to give you a definitive answer.
BlueChip
Well-Known Member
Yes, its an anti syphon device on the engine cooling system. When the engine is running there will be a water passing through the thick pipes leading from the heat exchanger to the exhaust elbow - a small amount of water will pass through the narrower tube which will vent overboard or into a cockpit drain.
When the engine stops air will enter the thin tube and break any syphon in the main cooling system and exhaust- preventing water from the exhaust trap being sucked back in the engine as it cools down.
It's important to make sure that this system is working - the end of the vent tube is liable to get blocked with salt crystals, and at least once a year you should have a good poke around and make sure there is a good jet of water coming out and check it from time to time
When the engine stops air will enter the thin tube and break any syphon in the main cooling system and exhaust- preventing water from the exhaust trap being sucked back in the engine as it cools down.
It's important to make sure that this system is working - the end of the vent tube is liable to get blocked with salt crystals, and at least once a year you should have a good poke around and make sure there is a good jet of water coming out and check it from time to time
DeeGee
Well-Known Member
[ QUOTE ]
Yes, its an anti syphon device on the engine cooling system. When the engine is running there will be a water passing through the thick pipes leading from the heat exchanger to the exhaust elbow - a small amount of water will pass through the narrower tube which will vent overboard or into a cockpit drain.
When the engine stops air will enter the thin tube and break any syphon in the main cooling system and exhaust- preventing water from the exhaust trap being sucked back in the engine as it cools down.
It's important to make sure that this system is working - the end of the vent tube is liable to get blocked with salt crystals, and at least once a year you should have a good poke around and make sure there is a good jet of water coming out and check it from time to time
[/ QUOTE ]I assumed it was an anti-syphon device, I was hoping someone else would have one,and know what was EXACTLY inside. My reason for asking was that I suddenly noticed, for the first time in about 5 years, water coming out of the air-vent hole. I have never noticed it before (not that that means anything more than my lack of observational skills!!). The water comes through once revs are up a tad, not at tickover. I thought that there was a one-way system involved so air could come in, but water not go out? Your description fits the operation I have observed, it is the fact I have never seen water coming through that bothers me. /forums/images/graemlins/frown.gif
Yes, its an anti syphon device on the engine cooling system. When the engine is running there will be a water passing through the thick pipes leading from the heat exchanger to the exhaust elbow - a small amount of water will pass through the narrower tube which will vent overboard or into a cockpit drain.
When the engine stops air will enter the thin tube and break any syphon in the main cooling system and exhaust- preventing water from the exhaust trap being sucked back in the engine as it cools down.
It's important to make sure that this system is working - the end of the vent tube is liable to get blocked with salt crystals, and at least once a year you should have a good poke around and make sure there is a good jet of water coming out and check it from time to time
[/ QUOTE ]I assumed it was an anti-syphon device, I was hoping someone else would have one,and know what was EXACTLY inside. My reason for asking was that I suddenly noticed, for the first time in about 5 years, water coming out of the air-vent hole. I have never noticed it before (not that that means anything more than my lack of observational skills!!). The water comes through once revs are up a tad, not at tickover. I thought that there was a one-way system involved so air could come in, but water not go out? Your description fits the operation I have observed, it is the fact I have never seen water coming through that bothers me. /forums/images/graemlins/frown.gif
Mirelle
N/A
I'd be a bit inclined to have a look at the water injection bend in the exhaust elbow.
I suspect there may be some scale or other crud partly obstructing it, so that when the throttle is opened some water diverts out of the antisyphon air tube.
This might save the cost of a new waterlock muffler and exhaust hose.
Er, don't ask me how I know this! /forums/images/graemlins/wink.gif
I suspect there may be some scale or other crud partly obstructing it, so that when the throttle is opened some water diverts out of the antisyphon air tube.
This might save the cost of a new waterlock muffler and exhaust hose.
Er, don't ask me how I know this! /forums/images/graemlins/wink.gif
ditchcrawler
Well-Known Member
My boat is a Hunter(British) & my anti-syphon device spurts water out of the side of the boat via a tube & fitting when the engine (Nanni 2.50HE 14HP) is running all of the time.I queried this with Hunter & they said that this is correct.There is another version of the anti -syphon device which simply has a flap on the top ie you do not have a tube with water running all of the time.
Benbow
Well-Known Member
Its not a big deal whether or not water flows from the breather – some do and some don’t – it depends on the back-pressure in the system and the flow rate vs the capacity of the trap..
However, if it suddenly starts flowing when it has not previously done so, I would be concerned that there is a blockage in the cooling water exit pipe or down stream of it, the point where it joins the exhaust elbow seems a likely culprit.
I assume water is still coming out of the exhaust ?!.
However, if it suddenly starts flowing when it has not previously done so, I would be concerned that there is a blockage in the cooling water exit pipe or down stream of it, the point where it joins the exhaust elbow seems a likely culprit.
I assume water is still coming out of the exhaust ?!.
Aeolus_IV
Well-Known Member
Often these have a one-way value in them, so air can get in, but water can't get out. Perhaps (if yours has) its failed open?
Regards, Jeff.
Regards, Jeff.
