John,
First of all, as an engineer/mechanic/metallurgist/blacksmith I can offer a very vehement opinion that piston rings will not fail due to an engine ingesting exhaust smoke and/or carbon-unless you managed to get them running hot enough to accept extra carbon into their crystalline lattice structure and then somehow got them cold quickly enough to trap that carbon (quenched 'em) thereby making them brittle. But, hey, they're already brittle to start with-they're about as hard as engineering can make them. However-if you DID have ring failure (whatever the reason-there are lots of other, legitimate reasons), then you'd smell exhaust fumes coming from the breather tube due to combustion blowby. So in that sense, he's right. If your rings have failed, you'll have other symptoms, like serious loss of power, contaminated oil pretty soon, and so forth. Easiest check? Take a compression tester to your boat and check each of the cylinders. If you've blown your rings, you'll see readings well below 50 psi. Carbon buildup is commonly seen at overhauls and it's routinely dealt with. But an overhaul, no matter how much or little carbon you've got, is expensive. If your rings are shot, you need one-or you need another engine. Sorry. But if your compression readings are good, I'd look other places starting with the exhaust manifold and working out to the transom. If you need another engine, I'm right on the verge of pulling a beautifully running and immaculately maintained Atomic 4 in order to install my experimental hybrid drive system <grin>. I hate to remove a perfectly good engine, but I can't experiment with it in there. and I could use some cash to pay for the rest of my gear. David Shaddock Shivering in Rockford, IL From: [email protected] [mailto:[EMAIL PROTECTED] On Behalf Of [EMAIL PROTECTED] Sent: Wednesday, November 21, 2007 6:20 PM To: [email protected] Subject: Re: catalina27-talk: Model 15/5411 Universal Engine Repair List Need advice. My Model 15/5411 Universal is ailing. Several months ago had the exhaust manifold replaced after replacing several freeze plugs (water leak). Soon thereafter the exhaust pipe riser developed a hole and as a result the engine compartment was flooded with exhaust smoke/carbon. The exhaust pipe riser was replaced. Soon thereafter I started smelling exhaust fumes. Bottom line. Mechanic has diagnosed the problem as piston ring failure caused by the engine ingesting the carbon exhaust/carbon. Due to the ring failure I have "blow by", that is, exhaust gases are blown into the crank case and exit the engine via the breather tube, which causes exhaust gases in the cabin. the smell that I have noticed. I am faced with an engine overhaul and some big time boat units. Rings need to be replaced and any other problems caused by the carbon build-up needs to be corrected, i.e. cylinder walls, bearings, etc. Does anyone have any experience with this problem? Any observations and/or suggestions would be appreciated. John Jennings _____ Check out AOL Money & Finance's list of the hottest <http://money.aol.com/special/hot-products-2007?NCID=aoltop00030000000001> products and top <http://money.aol.com/top5/general/ways-you-are-wasting-money?NCID=aoltop000 30000000002> money wasters of 2007.
