First, where are you?

pull the engine, take it apart and see what ya got before you go shopping, may be a lot lees money to fix it compared a new long block.

Mercruiser - the block is made for them by a foundry, I forgot if that is in IL or MI or WI. Merc states they are not using one GM part of anything for their newer marine built apps. Smart on their part for selling parts.Not good for the boat owner for competition part pricing.. Just like their outboards, one can not run down to the auto store and buy parts.

8.2? or 8.1?

Mid 2010 the 8.1 were gone for Mercruiser GM stopped producing the ---- 8.1 / 496 ---- Dec 31 2009.

For Mercruiser - 2010 / 2011 was the start of the 8.2 catalyst engines. nothing like the older 502 /. 454's.

Other than BUP, surprising the others in this thread did not read the SB...it's a quick one.

So if he needs an engine, and not under warranty, he is looking at seeing if this is repairable, paying about 20k for a new one, or looking into repowering with earlier, easier to find and less expensive engine. And not sure if that is even legal.

Because of the SB, my first call would be to local marina...if that doesn't go far, than Mercruiser themselves. Then go from there if need be.

can not change engine with older one IN THE USA from CAT to none cat. Unless he just buys an engine package outside from Merc - Merc whats the HIN and sells if its a CAT engine app --- a cat engine can only be ought thru them again if the boat HIN is a CAT install thru the boat builder. . But how one sets it up afterwards is on them with no warranty period thru merc.

Its actually EPA mandated. If this ran thru my hands it would have to be a cat engine installed -

For one the engine serial needs to be ran to see what was done and not done --- then go on from there. ALL CAT engine emission related stuff is warranty for 3 years / 480 hrs whichever comes first. I understand this is 5 or 6 years old engine app with NO warranty.

I would see what warranty work and what has not been done - I would use all that and talk to merc and possible selling dealing if they are still around to see if any help could be provided. I have been there before as a selling dealer and Merc can be helpful with their offers