Carbon Monoxide Problems - ugh!!

[Kurt]

So, I replaced all of my wet and hot exhaust a couple of months ago. Recently, I a friend noticed some smoke in the cabin and I noticed it as well. I also noticed that if I run my engine without the blower, my carbon monoxide detectors will read something in the 30's to 40's - they usually read 0 with the blower on and they never used to read that high with the blower off. I put one of my carbon monoxide detectors on top of the reversing gear, basically right underneath my exhaust flange from the manifold. I fired up the engine and the reading on it steadily rose - up to well over 400. So, my question is, is this normal for an A4 or should you be able to put a carbon monoxide detector right my your exhaust manifold with the engine running and have it read next to nothing (2 years ago, when I got the boat, I did this same thing and it only went up to about 40). If this is a problem, what is the solution? I already pulled the hot exhaust back off and put a new flange gasket on there with a little permatex, but it made no difference. Should I try to use more flange gaskets? Maybe use 2 gaskets instead of 1? Should I use more hi-temp permatex on the installation? The flange and manifold surfaces look pretty fair.

Input appreciated - I don't wanna die sleeping in my cabin on a long cruise!!

Kurt.

[msauntry]

Focus on the manifold and the hot pipe section of the exhaust. If it is wrapped in fiberglass insulation tape, you might have a hard time detecting a hole.

My cabin used to get pretty hazy, but it was from the crankcase vent.
I added the kit that plumbs it into the carb/intake so it burns those fumes instead. Could this be the problem?

Where is your blower vented to? Does your blower hose have holes or restrictive sharp bends that could limit its effectiveness?

Could you rig some sort of way to pressure test your exhaust? Blow into your transom fitting, but make sure nobody is looking

I almost forgot... its a long shot, but I had a small hole developing in my manifold from where it was rusting through. Look for any odd splatter signs in your engine compartment or listen for a "chuffing sound". Hold your hand close to the manifold while the engine runs and see if you can feel any puffs of air. This certainly let exhaust fumes escape.

[luvmyi36]

If you do not get the leak figured out with msauntry's idea of feeling and listening for the leak, would it be possible to create a smoking engine by adding a little too much Marvel Mystery Oil to the gas? I know that when I have gotten carried away with the MMO added to the gas, I see an overabundance of smoke out the exhaust and maybe this could lead you to the problem area. Maybe one of the more seasoned forum members can chime in with what would be too much MMO. Whatever the case, CO is bad stuff, and we would all hate to see you take an extra long nap.... (Sorry Russ, this an exception to your rule.)

[keelcooler]

Soap water test the fittings. I bet it's crank case blow by.

[Kurt]

Thanks for the input. I like the idea of soap water testing the fittings around the exhaust flange - never thought of that before. So, I wonder, does crankcase blowby contain significant amounts of carbon monoxide? Just wondering as my cabin doesn't get too smokey, but if blowby was/is an issue, can that contribute to elevated carbon monoxide readings on a detector that it put in the engine compartment?

[msauntry]

Good question. It set off my smoke detector, but I don't have a monoxide detector (yet). Not sure what its comprised of, but it was visibly hazy. The $75 kit completely fixed it. Its relatively cheap and its an easy kit to install.

You shouldn't have any smoke/haze/odor at all in your cabin.

[lat 64]

Blowby

kurt,
I have read that back in the 1950s, it was discovered that a great deal of the auto-produced hydrocarbons that caused smog was coming from the crankcase. Somewhere around hlaf. It was actually dirtier than the tailpipe. A lot of this hydrocarbon stuff is misted or evaporated lube oil and blowby gases. I' think CO is probably a significant factor.

Try the PCV thing.

Russ

[keelcooler]

I think if we all installed readable CO detectors in our motor boxes we would be blown away. No A4 blow ups from gas, however we lost a good marine mechanic at a large sailboat marina in Solomons MD,early 90's. Most CO deaths aboard boats involve gas generators and closed up cabins. Always vent the cabin when running the engine and if someone is napping below open forward and rear hatches! Diesel exhaust smells and gets you sick,but you don't smell CO and it kills. Main causes of death when pleasure boating,Drowning,hypothermia,AC electrocution and CO. Keep things safe gang!

[sastanley]

keelcooler..I knew that guy. His wife was pregnant with their only child at the time (the years might be a little off, I think it was early 80's, as she is an adult now.)

At any rate, still sad. I was pretty young myself at the time, but everyone said he was a great guy. One of our club distance races has a perpetual trophy named after him.

My powerboat buddy has a CO detector in his aft cabin. I would think in a sailboat we would have enough ventilation, but you really never know!

[keelcooler]

It may have been the 80's,it was a big workman's comp case. The boat was in the slip and I recall he was winterizing the A4. He's not the only one! I remember showing a power boat owner the metal fatigue pin hole in his manifold exhaust pipe that killed his grandson taking a nap below when everyone was on the flybridge . Found it by soap water testing with a spray bottle. Every year soap water test exhaust and propane fittings for leaks!

[Kurt]

I'm getting scared now Well, I'm always cautious about this CO stuff. I was just concerned that my CO detectors actually started showing readings when they didn't before - I could run the engine with the stairs off and the compartment open and the blower off and get a big fat 0 reading. I have a CO detector in the cabin right by the engine compartment and another one up in the V-Berth (a good place to have one as CO can collect up there if your hatch isn't open). I just recently had my hot exhaust replaced so I think I'm going to take the wrap off and do a soap and water test. I'm also gonna add an extra gasket to the exhaust flange - I would imagine more gaskets would help deal with imperfectly smooth mating surfaces - just a guess.

[Kurt]

Just to report back on this thread. I didn't go the route of soap water testing my exhaust fittings as my hot exhaust is brand new so I tried the PCV kit as the consensus seems to be that crankcase blowby does have CO and I was getting some smoke in my engine compartment and cabin (not much, but visible). The kit worked wonders. As I mentioned, before the kit, I put a CO detector on the engine (layed it right on the reversing gear which is right under my exhaust flange) and got a 400 reading! After installing the PCV kit, I did the same thing with the CO detector on the engine for about 20 minutes (blower off) and got a 0 reading. Some difference. I'm going on a cruise in a couple of weeks and am happy this worked out as I was feeling rather unsettled with the idea that people would be sleeping down below with CO. We will motor through the night and into the morning for about 15 hours.

[keelcooler]

I think Indigo and MMI could do a4 owners a service in marketing the PVC kit as a safety up grade in reducing CO in the cabin. On second thought the lawyers would have a fit. If someone installs a system and croaks,you could be open to a wrongful death case.
Anyway,always vent the cabin when motoring.