14 years of exhaust buildup - checked yours?

Yngmar

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This is what my exhaust connector looked like after I believe 14 years (new to me boat, but everything points to this never having been removed before). That's the bit on the MD22L-B exhaust elbow where the spent raw water goes in the elbow before joining the exhaust gas.

cloggy_the_connector.JPG


It was clogged except for a ~6mm diameter hole, not to mention the metal had actually crumbled away below the hose and hose clip (which lead to it leaking). The connected hose, apart from having turned porous had significant buildup too, but tapering off towards the heat exchanger, where there was no residue at all. I found this interesting, as the black crud must be exhaust gas residue, and to find it there must mean it gets blown quite a bit into the raw water system back from the elbow. The yellow stuff in the most recent layer must be from the antifreeze used to winterize the raw water system.

Engine is running fine by the way, although I'll be taking off the elbow in the near future to take a peek in there as well (and probably the heat exchanger insert too).

Thought this picture was worth sharing :)
 

Heckler

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24 Feb 2003
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This is what my exhaust connector looked like after I believe 14 years (new to me boat, but everything points to this never having been removed before). That's the bit on the MD22L-B exhaust elbow where the spent raw water goes in the elbow before joining the exhaust gas.

cloggy_the_connector.JPG


It was clogged except for a ~6mm diameter hole, not to mention the metal had actually crumbled away below the hose and hose clip (which lead to it leaking). The connected hose, apart from having turned porous had significant buildup too, but tapering off towards the heat exchanger, where there was no residue at all. I found this interesting, as the black crud must be exhaust gas residue, and to find it there must mean it gets blown quite a bit into the raw water system back from the elbow. The yellow stuff in the most recent layer must be from the antifreeze used to winterize the raw water system.

Engine is running fine by the way, although I'll be taking off the elbow in the near future to take a peek in there as well (and probably the heat exchanger insert too).

Thought this picture was worth sharing :)
£70 ish for that bit and I guarantee the £400 ish other bit will be as bad! I made one from 316 SS, wrote it up for PBO so its all in the back issues.
S
 
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