[C320-list] Muffler leaks and drainage

[jim brown]

The drain tap certainly could leak water if in the open position (screwed out). That's the drain that you're supposed to use if you crank the engine for more that 30 seconds before you try again. That is to prevent hydro locking of the engine (costly). Won't affect anything if it's left open but will drain water into the bilge. 

Not sure why you'd get a raw diesel smell from an exhaust leak. That to me smells like exhaust with a little diesel mixed in. I'm not sure how much raw diesel fuel gets into the exhaust under normal conditions where unburnt fuel is supposed to be returned to the fuel tank so it doesn't wind up in the exhaust. Also if there is some diesel fuel in the exhaust it would be diluted by the water from the aqualift muffler. A leak of fuel, however, would gradually work its way into the bilge via the compartment under the sink. Chased a small leak in the secondary fuel filter for quite a while on our boat. Smell was worse under the sink. 

Jim Brown


      From: Graeme Clark <cg at skyflyer.co.uk>
 To: Catalina list <C320-List at Catalina320.com> 
 Sent: Friday, January 13, 2017 2:49 PM
 Subject: [C320-list] Muffler leaks and drainage
   
Last summer, after motoring any length of time, we would get a diesel fuel smell in the aft cabin and  - i noticed  also - more strongly under the galley sink.
I know I don't have a fuel leak and I know that the exhaust system is good as far as the muffler.

I therefore am assuming either a leak from the muffler or from the exhaust hose itself, which is I think the original fit from 20 years ago and therefor probably perished!

So I will be replacing the exhaust hose and have removed the muffler to inspect at home. There is no immediate obvious sign of a leak but it isn't under any pressure, of course. Any suggestions as how to best test it?  Even if it isn't leaking I thought I might take the opportunity whilst out of the boat, to reinforce any weaker areas with glass mat and resin. But what ARE the weaker areas? I know others here have had problems with these mufflers on and off over the years.

Finally, there is what i assume to be a T-shaped drain tap on the side of the muffler, but I was surprised to find it in the fully unscrewed position (in other words fully counter clockwise). has it vibrated open, is that the ‘leak' - or does this drain valve work in the reverse sense to ‘normal’?

Thanks in advance for any guidance

Graeme
#366, 1996, Oskar, Falmouth UK

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