Is this a bad exhaust elbow?

[Twolane]

From a late 70s Mercruiser 165. Is this a casting that's been eaten through? I didn't expect to see water channel directly open to exhaust flow.

Alternatively, if this is how it's supposed to be I'd appreciate it if someone would explain to me how this sytem works. As it obviuosly doesn't work as I assumed. Area in question is highlighted in the photo with a red circle.

Thanks.

 

[Stevens520]

Re: Is this a bad exhaust elbow?

Nope;looks like those holes were cast in.May need to clean out the water passages if you aren't getting any water flow through it though; they tend to get plugged with crud.

 

[Twolane]

Re: Is this a bad exhaust elbow?

Nope;looks like those holes were cast in.May need to clean out the water passages if you aren't getting any water flow through it though; they tend to get plugged with crud.

Agree the holes look as if they're part of the original casting. Looking closer and running a wire wheel through the inside it looks as if a steel sleeve might have rotted away inside this thing too. Perhaps that's what missing that separate the water from the exhaust flow?

Actually..... let me go check the spare parts pile for comparison.

Here's another elbow off another Mercruiser 165. Probably a couple years older. Is the originally pictured part a casting with a necessary sleeve eaten away? Is it just two different but functionally equivalent parts? Which is the better to use on the buddy's boat that is coming out of hibernation?

 

[Bt Doctur]

Re: Is this a bad exhaust elbow?

http://www.michel-christen.com/ExhaustElbows.pdf
some had sleeves and some didnt use sleeves.

 

[Twolane]

Re: Is this a bad exhaust elbow?

http://www.michel-christen.com/ExhaustElbows.pdf
some had sleeves and some didnt use sleeves.

Interesting article. Since it's thesis was the methodologies employed to solve the problem of water in the exhaust (or that might lead to it) I take it that the first pic I shared above is normal? That the water jacket of the manifold is normally open to the exhaust chamber?

While after only the short read I still don't quite get my head around that as an application I am still left with the same question I started with. Of the two manifolds I've got here and pictured above is there a preference between the two as to which to use?

 

[Twolane]

Re: Is this a bad exhaust elbow?

Thanks to everyone that looked. Was hoping someone could offer specifically whether that first manifold picture was actually cast that way or simply looked as if it was. The other "spare" manifold is cleaner internally so, barring specific informed guidance to the contrary, will go back with that one.

 

[scubadoo73]

Re: Is this a bad exhaust elbow?

I had to replace my elbow on my 1977 model 888 and I have port side with sleeve and starboard side with out and that hole is casted that way

 

[Twolane]

Re: Is this a bad exhaust elbow?

I had to replace my elbow on my 1977 model 888 and I have port side with sleeve and starboard side with out and that hole is casted that way

Thanks very much. Eyes-on of another piece cast the same way is reassuring. Appreciate it.

 

[Pete104]

Re: Is this a bad exhaust elbow?

If you get water in a cylinder, atleast you know where start looking.