Yanmar exhaust water trap drain plug

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Following on from the discussions about the need to inspect/replace the mixer elbow this issue is just a little further downstream......

My 4JH2E has a stainless steel exhaust water trap about the size if your average yottie bucket. Output from mixer elbow inbound and connection to hull fitting outbound. In the bottom of said water trap is a blanking plug to facilitate draining, for winterisation presumably. The plug had started weeping of late so today I thought I'd put a spanner on it to replace it - it fell apart as soon as I tried to unscrew it, completely rotten. Dezincification I presume. I managed to get the remainder of the plug out, it was so soft it was almost a paste. Replaced with another brass blanking plug, will be on the phone tomorrow to see if I can source a bronze 1/4" blanking plug.

So moral of the story is to replace the plug annually I guess, before it has a chance to turn in to paste. Maybe people already do this as part of annual servicing? Not heard or read about it before though. Any other experience and/or opinions?

 

[vyv_cox]

I had exactly the same experience with my diesel tank. The brass drain plug began leaking and I tightened it about a quarter of a turn but did not like the feel of it, so went no further. A few weeks later the tank was almost empty when I removed the plug to fully empty it. After unscrewing it about a quarter turn it fell out! The threads had almost disappeared due to galvanic action, presumably due to small amounts of water in the bottom of the tank over 20+ years.

 

[NormanS]

A friend with a boat the same as mine had this happen to his stainless mixing chamber, fitted with a brass? plug. I checked mine, and it has a stainless plug. Seems a sensible way to go.

 

[vyv_cox]

A friend with a boat the same as mine had this happen to his stainless mixing chamber, fitted with a brass? plug. I checked mine, and it has a stainless plug. Seems a sensible way to go.

But then the two might gall together! Nothing is perfect

 

[prv]

But then the two might gall together! Nothing is perfect

Kindred Spirit had a plastic one, with a plastic bung. Though I suppose that in turn is vulnerable to melting if the cooling water is interrupted...

Ariam also has a plastic trap; I've no idea if it has a bung as it's jammed in behind the fuel tank and hard to get at. Instead of trying to drain it, I just take the exhaust hose off the elbow (inspect the internal condition of the elbow at the same time) and tip a load of non-toxic antifreeze down it :encouragement:

Pete

 

[vyv_cox]

Kindred Spirit had a plastic one, with a plastic bung. Though I suppose that in turn is vulnerable to melting if the cooling water is interrupted...

That has happened to me. We sailed north to Scheveningen harbour on a choppy sea. About half a mile off I started the engine and just as we were between the breakwaters the temperature alarm went off. I motored on for a short distance and anchored inside the harbour. The pump had failed to prime, once sorted we continued onwards inside. No further action was needed but later in the season I inspected the trap and found the internal baffles melted.

 

[westhinder]

Following on from the discussions about the need to inspect/replace the mixer elbow this issue is just a little further downstream......

My 4JH2E has a stainless steel exhaust water trap about the size if your average yottie bucket. Output from mixer elbow inbound and connection to hull fitting outbound. In the bottom of said water trap is a blanking plug to facilitate draining, for winterisation presumably. The plug had started weeping of late so today I thought I'd put a spanner on it to replace it - it fell apart as soon as I tried to unscrew it, completely rotten. Dezincification I presume. I managed to get the remainder of the plug out, it was so soft it was almost a paste. Replaced with another brass blanking plug, will be on the phone tomorrow to see if I can source a bronze 1/4" blanking plug.

So moral of the story is to replace the plug annually I guess, before it has a chance to turn in to paste. Maybe people already do this as part of annual servicing? Not heard or read about it before though. Any other experience and/or opinions?

I had exactly the same issue on my first boat, stainless water trap with a brass draining tap, which corroded away in no time. Replaced with a stainless plug which lasted until I sold the boat many years later. Quite happy with the plastic Vetus water trap in the current boat so far.