Mercruiser 8.2 w/Cats & Closed Cooling Question

Deadon04

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Dec 11, 2023
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I am on the leading edge of these good news bad news 8.2 EC engines. Have a pair of 2011 8.2 Base(380 HP) cat engines in a sterndrive that we use in salt water. Bad news is as reported the replacement parts are catastrophicly expensive, especially the catalyst canisters. There is a good news story though, sort of. We replaced the full exhaust system as preventative maintenance, having never had any overheat issues after 11 years of saltwater use and 600 hours. 10 of the 12 catalyst canisters were reusable, one of them got cracked during removal and one had corroded internally somewhat, but others worked. The manifolds and collectors did have some rust build up in the water jackets that would have been an issue sooner rather than later due to reduced water flow, but not anything near corroding through the walls. Again never saw any cooling issues at all. The elbows are actually stainless and had no corrosion issues at all and were able to be put right back on. The most corroded and rusted parts were the manifolds as they also are prone to external rust from condensation in our salty environment. The collectors had some rust in the water jackets but externally were fine. These engines were extremely diligently flushed after EVERY use with salt away, not saying salt away has any magic, but given the long use period of the manifolds hard to say it didn’t help.

Now, given the choice between a nice Mercury Verado 400 and the 8.2 sterndrive, I’d rather the verado. Ease of access for maintenance, none of the bravo 3 maintenance and a host of other reasons. Should every 8.2 sterndrive be melted down for scrap? not if you already have them and they are well maintained.
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
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Jul 23, 2011
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48,054
More than 5 years on manifolds in salt is amazing
 

tpenfield

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Jul 18, 2011
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11 years manifold life is really good . . . probably brings the cost of the exhaust maintenance down to about $1,000/year. o_O

I run in the salt with I/O's (sterndrives) . . . full closed cooling is the way to go, so the 8.2's are off the list (for me) since they are a 'half' system. On my latest boat purchase, I got the 6.2 SeaCore engines instead . . . but sure miss having the big blocks. :(
 
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