What evil lurks?

[Roger Long]

First off: Kudos to Mainesail for pointing out the need for a siphon break in the engine raw water line. I never thought about it because mine goes through a hot water tank high in the boat and I never heard of it being a problem on an E 32. I got in today and eyeballed it. Sure enough, on a very long tack, rail down as I'm wont to do, it could back siphon and fill up the muffler and engine. I could be doing some very long port tacks on the way over to Nova Scotia.

While taking stuff apart to find a place to install the loop, I discovered that there were brass fittings under the hose connections to the hot water tank. The down side of buying a fresh water boat is that people aren't as careful about these things. Having one of those break off could shut me down as definitively as getting a line wrapped up in the prop.

This fitting on the exhaust elbow has me puzzling. It looks like brass when I scratch it with a screw driver but it has what looks like the Yanmar factory paint on it. It's going to be a bitch to get into replace bacause it's one of those head down, arms length situations.

Does anyone familiar with Yanmars recognize this fitting and know whether it is brass or bronze?

 

[Ross]

Can you put a drop of HCL on it? If it foams it is probably brass. Is there even room to turn it?

 

[Hermit Scott]

I would really like to know how to tell the difference between the two also.
Ross, where are you getting HCL, just have that laying around huh?
Roger, you do have a zinc in your raw water system. Doesn't that save the brass, iron and other more noble metals?

 

[Ross]

HCL=Muriatic acid

 

[Roger Long]

Roger, you do have a zinc in your raw water system. Doesn't that save the brass, iron and other more noble metals?

Yes, but zincs can only do so much, especially when the water is flowing.

 

[Nik]

You can get Muriatic acid / HCl at most any Hardware, Big box hardware, and or Pool supply store.

Nik

 

[Hermit Scott]

Why does it matter that the water is flowing? Isn't galvanic corrosion due to electron transfer that's moving at the speed of electricity anyway? I forget the chemistry exactly but vaguely remember the principle. Water is flowing through the engine also on raw water cooled, through iron but their zincs work alright to stem corrosion.
Just tie a halyard around your ankles and have someone winch you down and be done with it. lol

 

[Ross]

Why does it matter that the water is flowing? Isn't galvanic corrosion due to electron transfer that's moving at the speed of electricity anyway?

If the water is stagnant eventually it will be depleted(neutralized) and cause no further corrosion.

 

[Stu Jackson]

Kinda assumes one doesn't USE their boat

and becomes somewhat a moot point for those of us who do! Like those of us on this board!

 

[Hermit Scott]

What do you seal your exaust elbow with in the threads?

 

[Ross]

Teflon filled paste pipe joint compound.

 

[kloudie1]

I can't help, Roger.. I know the Yanmar part number is 124070-13300 and it costs about $15, but I can't find what it is made of .. I have inspected mine a couple of times and not noted any corrosion or anything that looked like de-zincification. So far as I know, mine is the original that came with the engine in '85. I remember when I changed the elbow several years back that it came out quite easily.

 

[Roger Long]

I can't help, Roger

Actually, you could help. Does yours look like that? If it is an original Yanmar part I think it's a pretty safe assumption that it is made of an alloy suitable for the job. I'm just trying to determine if it is another of the OP's make do's that were OK in fresh water but could be big problems now that the boat is in salt.

I'd just pull it and put in a new on but, given the horrible access, if it breaks off I'm really in a pickle.

 

[Stu Jackson]

Why not?

I'd just pull it and put in a new on but, given the horrible access, if it breaks off I'm really in a pickle.

Why not get the part and have it on hand if you do eventually need it. You know, the old "cruising is repairing things in exotic harbors" routine.

 

[kloudie1]

What Evil Lurks

Sorry about the time to get back.. computer is doing strange things.. Yep, it is a Yanmar part but the discription says "Joint, PT 3/8 Pipe" .. Strange that Yanmar would have an English Pipe thread part, but there it is.. Here is a shot of mine (with tteh vented loop) .. not as clear as your picture.. You can see that they are the same.

 

[Roger Long]

You can see that they are the same.

Well that's a relief. Together with the paint and what I can see by visual inspection, I'm sure enough that it's an original Yanmar part that I won't mess with it, at least until I pull the elbow for inspection which will be next year, maybe. That fitting had "nightmare" written all over it. It would probably be easier to pull the engine than to try and replace it in the boat.

Thanks very much.

 

[Dennis W.]

Roger, as others have confirmed it is a Yanmar part. I replaced my mixing elbow 4 years ago, long story, and the new elbow came with that fitting already installed.