Posted by Bruce, CC 27 MKIII, (22.214.171.124) on May 28, 2004 at 14:54:30:
Some time back I saw a post about checking the exhaust pipe. On many (most?) Atomic 4's, this is comprised of an exhaust flange, into which is screwed a number of pipes & elbows made out of 1 1/4" standard black pipe that you can get at your local hardware store. Thing is, after 25+ years, they tend to rust out, but you can't really tell because they're usually wrapped in ASBESTOS cloth which is held in place by wrapped wire.
You want to remove that wire and asbestos cloth. You can replace the cloth with a thin layer of unfaced fiberglass batting & wire after you are done. Check the connections & the pipes for leaks.
Luckily, we checked ours before it went in the water this year after I saw a little exhaust leak coming out through the wrapping. Sure enough, I undid the wire, took off the cloth, and the pipe literally fell apart in my hands!
A failure in the pipe at the wrong spot can cause 1). Poisonous carbon monoxide buildup in the bilge and the cabin, or 2). The exhaust spitting cooling water into your bilge, which of course will happen when you're trying to make your way through nasty conditions and the pipe breaks!
Our exhaust flange was fused to the pipe, and we also needed a connection for the exhaust hose onto the pipe, but both were readily available from Moyer Marine. I was, however, EXTREMELY fortunate to have exhaust flange bolts that came out very easily. Thankfully, they didn't break off when I was removing them.
Hope this helps,