Have not seen or heard of too many problems with the stern drive boats, just the v-drive applications, so you guys can relax! The venerable small-block Chevy lives on despite Sean H.

Well I have gotten to become an expert on Merc 6.2's since I have had 4 fail this summer. The original 6.2's had 215 +/- hours with only a lift pump failure (fuel pump) and one IAC valve. Then the fun began, one ate a valve due to improper exhaust angle according to Mercury yet they approved the design when the boat was new in 04 but in 07 they claimed it was too slight of an angle (3 degrees too little for their new standards). Boat has Merc extended warranty so after a lot of complaining they changed both motors with reman motors.

With all new exhaust ($4500 cost to me) out to the tips the next two 6.2's went in the trash with less than 2 hours run time. I had one motor fail the mechanic had the other one fail on a sea trial. Merc explained the failure this time was in the reman process/ valves tolerances set too tight and after heat expansion they go boom. Now they put new blocks in and I am going to dinner tonight on the boat. 2007 boating time was about 4 hours in 10 months due to 4 1/2 months in/out of the shop.

The 6.2's have been good overall but I would be suspect of the reman. motors. The warranty cost on all this was about 48K. For that I could have gotten two new 496's!

To my knowledge the MX 6.2 is a factory built 377 cui while the 383 MPI is factory RE-manufactured with an over bore of .030" ...

To further complicate matters:
Mercruiser 377 CID__ 4.00" Bore X 3.75" Stroke
GM Crate 383 CID __ 4.00" Bore X 3.80" Stroke
Reman 383 CID __ 4.030" Bore X 3.75" Stroke

Cozzi all of our problems were in sterndrive boats!

Wow, have not been seeing that at all here. I thought maybe the 340 SeaRay Sundancers were too heavy for that package and they were over worked.

Now you got me scared also!!! I was going to order 2 of these in the next couple of days. I can get a really good deal on 2006 6.2's which were pulled for an upgrade. My application is in a 11,000lb express cruiser which has 250hp 5.7lx engines coupled to BravoII drives. Mostly running cruise rpm @ 3200-3400 rpm @ 30mph. Average season hours are about 85. WOT is maybe twice a season for a few minutes at most. Seems like older posts have nothing but good to say about the 6.2. The existing 5.7's are more than sufficient for this boat but wanted to upgrade mostly for EFI and all the newer technology that goes with it. Is there some kinda design change on the newer engines? What's going on? Help!! Maybe I should try to find 5.7's @ 300hp due to proven reliability?

OR maybe this is why Merc Remanufacturing seems to have an endless supply of 383 engines by rebuilding 6.2 failures?

I would love to know too. I'm looking to buy a Formula 280 ss with twin 6.2's .

Most of the problems I have seen have been are with big cruisers that should have 454's.

I have run the snot out of a 383mag in a little Donzi with no problems.

300 hrs no problems,but carry an I.A.C valve.