Offshoreonly.com - CMI Problem Help!

I had what sounds like the same problem that you are experiencing. On my boat, I had to remove the headers from the engine to get that joint apart - there was not enough room to slide the tailpipe aft to separate the joint. I have a 500EFI with silent choice, though. We found many of the welds "weeping" on the CMI's when my friend and I water pressure tested the header (regulated water line pressure was 60 psi). The welds from CMI were rather poor quality at the start/stop points - the craters at those places were leaking. Additionally, at the aft flange, there were several "cracks" in the welds and face of the flange. Also, the reversion cone inside the header looked like swiss cheese (316L stainless ??? :rolleyes: ) . These headers were only 2 years old with 120 hours on them and were used in fresh water and some brackish water and flushed after every use. My friend took the header apart and rewelded many of the welds. He did such a good job you could never tell that any work had been done! The face of the tailpipe had a bunch of divits/pits, too, but you really can't pressure test the silent choice tailpipes, though. We cleaned up that flange face, too, and now I don't have anymore drips from that header. I am not too impressed with their headers, so far ... :(