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General fresh water cooled system question

N

NedH

New member
I've bought a long block and will soon begin to dismantle my "stuck" 5.0 liter Crusader and swap the parts over to the long block. Looking at the risers and other exhaust parts I noticed quite a bit of internal corrosion (the boat is in salt water). The engine had just over 500 hours (I have the original hour meter), so, presumably, the corrosion must be normal for an engine of those hours, but still seems like a lot. But, what are knowledgeable thoughts on: either having the parts cleaned in muriactic acid or replacing with new? I'd hate to go through this hassle only to have later issues with the exhausts.
Any thoughts?
Thanks, Ned
 
As a general rule, if you are thinking about re-using the 'raw water cooled' exhaust components, I'd say it is false economy. Reuse of the parts that are cooled with the coolant may be feasible as long as they are serviceable. Typically, this means the manifolds and the concern is the gasket sealing surfaces need to be true.

On a typical V-8 FWC crusader configuration, the risers and elbows would be throwaways, especially in saltwater.

Its my opinion that you can't rely on the hour meter to tell when parts are no longer serviceable. When it comes to raw water cooled exhaust parts, idle time is a lot more detrimental than operating time.
 
makomark said:
As a general rule, if you are thinking about re-using the 'raw water cooled' exhaust components, I'd say it is false economy. Reuse of the parts that are cooled with the coolant may be feasible as long as they are serviceable. Typically, this means the manifolds and the concern is the gasket sealing surfaces need to be true.
Fully agree!

On a typical V-8 FWC crusader configuration, the risers and elbows would be throwaways, especially in saltwater.
Some risers/spacers are within the closed loop, in which case they are more than likely re-usable.
Elbows on the other hand, are always seawater cooled, and should be replaced.

Its my opinion that you can't rely on the hour meter to tell when parts are no longer serviceable. When it comes to raw water cooled exhaust parts, idle time is a lot more detrimental than operating time.
Agree again!
Click to expand...


Even while the term Fresh Water Cooling is still used by some today, it is a misnomer and is a carry over from the very old days.
These should be referred to as a "Closed Cooling System".
 
Thanks guys. After getting out in the Piscataqua River's ferocious currents on only 1 engine, I have zero interesting in having that happen again. New stuff here we come.
Hey Ricardo- Since I'm one of the old guys (75), can I still refer to it as FWC? :)
Ned
 
Ned, I’m also in my 70s.
Old dog or new dog…… these are technically a “closed cooling system“.
Use whatever term you chose..... we’ll know what you mean.
 
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