[C320-list] Muffler leaks and drainage

[Graeme Clark]

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

———————————————————
I work irregular hours and often write emails late in the evening and at weekends; that doesn’t mean I expect you to do the same; reply when convenient!

[pat reynolds]

if you have a muffler or muffler hose leak you should be getting water in the bilge and you could actually see the leak when the engine is running.  It seems unusual that the drain cock would be open and you not get water in the bilge, unless it was clogged.  if you are not seeing water coming out of the muffler or hose your smell is coming from elsewhere     as far as mufflers go if you got 20 years out of the muffler you are ahead of the game.  If it does leak don't bother trying to fix it, I did this and it kept leaking.  Get one from catalina but you have to either send the original back to them as they have several molds or have them send you photos of the ones they have made over the years.

[Warren Updike]

I'll be interested in this thread because the petcock on our muffler, too, can be open when running and nothing comes out. For winterizing purposes, I've tried to drain the muffler with nothing coming out. I have removed the petcock and inserted a coat hanger in to see if there is some obstruction--nothing. I can't know what is inside this thing; but, from the expected design there is no reason why I shouldn't get exhaust and water coming out when running.

Warren and Pattie Updike
1994 C320 "Warr de Mar" #62
Middle River, Chesapeake Bay

[Ken Geiger]

The Muffler box on #765 Northern Dream does drain out water when the Pet cock (Aft lower starboard corner) is removed for winterizing. Engine is not running. Valve will not open as it is seized shut so I just remove it.

Regards

Ken Geiger

[Troy Dunn]

Graeme

We discovered our muffler was leaking mid summer. As others have mentioned
once this starts to happen you can mess around with temporary repairs but
it is unlikely your repair will last very long. By the time we realized
what was really going on, the area under our engine was filling with enough
water after a day of sailing and motoring for maybe half an hour that the
water was overflowing that compartment and moving into the salon bilge.
Once that happens it's pretty easy to see that the muffler is your problem
as the failure point is the seam between the bottom panel and the top box.
This seam faces down actually so what you should notice is a vibrating
pool of water around the muffler that spills off the mounting deck and
beneath the shaft. Figuring out exactly where the leak is coming from is
more challenging. To do this you need to remove the muffler from the boat
and seal it up. I used sandwich bags and rubber bands. Use a compressor
to add a very small amount of pressure. I just poked a hole in one Baggie
with the nozzle. Use soapy water as a leak detector. In our case two
seam edges had failed. I used my dremel tool with cutting wheel to cut a
slot at the seam down both edges and used JB Weld. I also drilled out the
bolt holes and reinforced them with small copper bushings per the article
on the web site using epoxy as an added measure...in for a penny and all...

This repair got us through the season, but by late October the muffler was
leaking again. I shipped it to CD in November.

One interesting anecdote. Our muffler leak actually revealed a small fuel
leak in the lifter pump. We noticed a very small sheen under the engine.
We got a cheap set of offset screwdrivers and tightened the screws around
the pump and that fixed that leak....and we no longer noticed the 'exhaust
smell'. You may want to see if you have a similar problem.

Also, If you don't have water in your bilge then your muffler isn't
leaking.

Troy Dunn
Hull#514

[Graeme Clark]

Just to clarify: we do have water in the bilge after motoring. More than you can account for simply from sterngland dripping I think.
I actually think it's the exhaust hose that's the problem rather than the muffler but wanted to check it anyway now that I have it out the boat
Thanks for all good advice
Graeme

Sent from mobile: please excuse typos etc.!

[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 <c...@skyflyer.co.uk>
To: Catalina list <C320...@Catalina320.com>
Sent: Friday, January 13, 2017 2:49 PM
Subject: [C320-list] Muffler leaks and drainage

[sail-ability sail-ability]

If I may beg to differ with the statement below regarding 'unburnt
fuel'..... unburnt fuel is fuel that has been delivered by the
injectors(diesel engines) into the cylinders and for one reason or
another is not completely burnt. It goes out the exhaust and there is
no way that it can/is returned to the fuel tank. The injectors
however are delivered much more fuel than can be injected into the
engine. This excess fuel is then redirected to the fuel tank and is
used to cool the injectors. If you feel the fuel tank after a long
period of running you will detect that it is quite warm and this is
why. Check your engine next time you are aboard and you'll discover a
common fuel line connecting the injectors and leading back to the fuel
tank.

Just for the sake of argument.

JohnM

1999#574

--------------------------------------

[Graeme Clark]

Thanks all, for replies and comments so far.

I’m pretty sure that it’s not a fuel leak as there is no evidence of any fuel beneath the engine or the shaft. Water, of course, runs away and evaporates without trace, and there is a drip from the stern-gland anyway, which may mask other leaks, so its not always obvious where it has come from, but any fuel leak would leave evidence - an oily residue etc.

There is no obvious sign of a leak from the muffler but i will pressure test it as suggested to be sure. However I suspect that it is sound. If that is the case, then reinforcement will be exactly that - reinforcement, not repair. Some of your comments and the articles on the website have given me a good feel for how to do that.

I do get water in the bilge after the engine has been running, but it doesn't really smell of exhaust or fuel. (nor is there a film of fuel on the surface)

as far as I am aware there is no fuel lines routed anywhere near the galley sink. I think the smell is coming from the exhaust hose that is between the muffler and the hull outlet. Any liquid in that area will find its way to the bilge but firstly has to run between the inner and outer skins and because of the construction of the pan where the engine bearers are, it has to route around the port side of the engine bay and that takes it under the galley sink.

I have probably wrongly described it as a smell of fuel - it is more an exhaust smell really. Although the carbon monoxide detector has never triggered, (i don't think diesel engines produce much CO if I recall correctly)

So basically its a matter of me checking everything and replacing an old hose anyway.

the only other culprit might be the hoses to/from the water calories, but i cannot see why they would have any smell; its cooling water which is closed system, that heats the calorifer I think?

I’ll report back after testing the muffler and refitting with new hoses, next spring.

Graeme

[Warren Updike]

FYI a Chesapeake neighbor 320 #4 has replaced his Catalina muffler with a Vetus "Water Lock" muffler. I checked with him a few times over the years and he remains happy with it. There are other brands out there. Also, some available on Amazon and marine online stores.
I don't know the cost of a Catalina muffler. The production units seem to run in the $400-700 range. I haven't really looked into it.

Warren and Pattie Updike
1994 C320 "Warr de Mar" #62
Middle River, Chesapeake Bay

-----Original Message-----

[Troy Dunn]

Warren et. al.-

We just sent our muffler to CD in November. The cost of the muffler and
drain valve which is sold separately and which you have to tap your self is
almost $500 by the time you factor in shipping both ways. We should be
receiving the muffler in the next month or so I suspect.

Troy
Hull #514

[Greg Flanagan]

I got a new muffler from Catalina (Florida). I sent (email) an annotated set of pictures with all the dimensions, angles, and size of the holes drawn on the pictures. Sort of quick and easy shop diagrams. They sent the new muffler within the week, I saved the extra shipping, and brokerage fees, and the muffler fit and works perfectly. Much thanks to the folks at Catalina, especially Len Keller.

Greg Flanagan
Hoop Dancer #1076
Sidney, BC

[Dick Walker]

Has anyone ever used The drain? Out first boat was a C-30 '86. Same design

On that boat I replaced I replaced the muffler with one off the shelf from WM

THE BIG DEAL is know how much you can crank the starter. Overfilling the tank would send water back up stream and would not be good

Cheers



Dick Walker
740 Olive Ave.
Coronado ,CA 92118
619.435.8986

[Greg Flanagan]

Never. But only because my Yanmar has always started within a few seconds. You need the drain if you crank the engine for a number of minutes, or you will suck water into your engine-yes not good!

Greg Flanagan
Hoop Dancer #1076
Sidney, BC

[Ted Harrison]

Greg, was the drain installed or do you have to do it yourself after?

What was the cost, if appropriate to ask or send me the info thar...@innovations-plus.com

Tks

Ted Harrison

[jbrow...@yahoo.com]

I think some have suggested using a hump hose in place of the standard one between the elbow and the muffler to reduce vibrations. Anyone done that?

Jim Brown

Sent from my iPad

[Allan S Field]

I tried that on hull #808 years ago but there was not enough room to install.

Allan S. Field

[Greg Flanagan]

The drain was installed with the unit at the factory. The muffler cost $375.

I put marine grade rubber door seal on the base rim which made it vibration free and quieter as well as making a better join to the hull.

Greg
Hoop Dancer #1076

[Warren Updike]

Since our muffler doesn't seem to drain via the petcock, in order to over crank the engine, I close the raw water thru-hull to prevent back-flow. Should I approach 30 seconds of cranking, I will also close the thru-hull.

[John Frost]

I also put a rubber gasket under my new muffler. Then instead of mounting it with the 4 screws where the leaks all appear, I held it down with a heavy nylon strap

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[Jeff Hare]

Hi Jim,

You don't need the hose hump. I installed the flexible corrugated exhaust hose, Trident/Shields 252 series I think. So much more flexible and nice smooth interior wall. Takes the vibration out. It's quite expensive, like $20/ft, but you don't need very much at all. Certainly much cheaper than repairing a muffler.

-Jeff Hare
#809

[da...@jensenshouse.com]

Here are the details of my mixing elbow / aqua lift muffler replacement project.

I have about 500 hours on a 2004 C320 with a Yanmar 3GM30F-YEU. The mechanic recommended I change the mixing elbow in the next 12 months. The U Mixing Elbow inside was corroded at the point where the raw cool raw water mixes with exhaust. The riser appeared to be in good shape but the two parts looked to be bonded together and my mechanic told me to replace the entire assembly Elbow, riser and join. I read several owners accounts of failed mixing elbows and mufflers / muffler repairs. The lead time to get a muffler from Catalina was estimated to be 2 months. The general consensus was to replace the muffler after about 10 years. Mufflers seem to fail mostly near the screw holes in the corners. Some owners think this is due to vibration from the engine exhaust hose. I used Jeff Hares rule and decided to replace the muffler on my schedule instead of the boats schedule especially because of the 2 month lead time for the muffler. The cost of the muffler from Catalina was $374.

I contacted Ken Roy at Catalina and gave him my hull number and some pictures and dimensions of my existing muffler (it is for sale now). Ken asked for some more dimensions. Ken sent me back a picture of the muffler he proposed to make for me and requested payment. It took about 2 months total to get the muffler.
I ordered the gasket, mixing elbow, SS joint and riser exhaust from Bayshore Marine(see below). Next, I considered the muffler vibration issue. Some owners felt that a hump hose would isolate the vibration from the engine to the muffler. The existing wet exhaust hose connecting mixing elbow to muffler input was a 22 inch 2 in. id. I decided replace with 2 hose segments of more flexible trident corrugated exhaust hose joined together with an exhaust hump hose I purchased from Catalina Direct.

Here are the details. The procedure took about 3.5 hours including driving home once.

1. I turned off the raw water thru hull, disconnected the 3/8 hose connection at the elbow, the 4 riser exhaust bolts came off with no problem. Then I disconnected the elbow from the 2 in. exhaust hose. I used a radiator hose pick to remove the hoses. They came right off with no problem. Don’t sweat removing the hoses.

2. I took the old elbow assembly home where I used it for reference to create the new assembly using a vise. I don’t believe you can create the new assembly without the help of a vise and 2 large adjustable 15 in wrenches. Don’t try to make the new assembly on your boat! You will need to twist the 3/8 in input 180 degrees then you will need to create the exact same angle as the old elbow by threading the joint into the elbow and exhaust riser. I used high temperature anti seize on the joint threads before assembly.

3. I used a gasket scraper to easily remove the old gasket. Then I applied some high temp gasket seating material to both sides of the new gasket and bolted the elbow assembly to the motor.

4. I removed the 4 stainless screws securing the muffler to the boat and I removed the output exhaust hose from the old muffler using the radiator hose pick. The hoses come off the muffler without any problem. The muffler comes out of the boat without any problem.

5. I put the new muffler in place and connected the output exhaust hose without any issues. I found the screw holes on the new muffler did not match the screw holes on the muffler. I could get the 2 screw holes forward to line up but then the aft screw holes with not align with the existing holes. Access to the forward inboard screw is somewhat limited so you will want to match the forward inboard screw with the existing hole then use a drill motor to self tap new holes with the muffler in place. The existing self tapping screws were in good shape and I did not need to drill pilot holes, I just drove the screws into the glass with the muffler in place after I screwed down the forward screws. Apply a good amount of silicon grease to the muffler drain.

6. I used a sawzall to cut an 8 in and 13 in segment of corrugated exhaust hose then I joined them with a hump hose using double hose clamps on each side of the hump hose. Then I connected the hose to the mixing elbow and the input side of the muffler.

7. I turned on the thru hull and ran the engine. White fiberglass chips from the new muffler were spitting out the exhaust for a while. No leaks. The hump hose appeared to do the job limiting vibration. I left the rear engine cover off and took the boat out in open water and ran the motor up 3000 RPM. I went below and to my surprise I saw smoke coming from the exhaust riser side of the stainless steel joint nut! No water. It appeared that the joint was oozing and burning anti-seize. After about 10 minutes this smoking stopped. I’m assuming this is normal but it spooked me. I’m going to put a co2 monitor in the aft cabin to make sure I don’t have gas leaks.

Parts:
bayshore marine:
128370-13201 gasket $4.92
124070-13520 U mixing elbow $169.33
128370-13610 riser exhaust $130.39
104214-13580 joint $28.79
Note:
27233-250000 plug comes with 124070-13610
124070-13300 elbow 3/8 comes with 124070-13610

Parts from Catalina Yachts (K...@catalinayachts.com)
1 Muffler $374 plus Shipping

Parts from Catalina direct:
High Temp Anti-Seize Compound (#Z2858): 1
Item Total: $15.95
Exhaust Hump Hose 1-5/8"I.D X 6" (#Z2152): 1
Item Total: $31.49

Tools Harbor Freight
8" Radiator Hose Pick $3.99
Carbon/Gasket Scraper $2.99
High Temp Gasket seating compound

MMI Marine
TRI252-2004
TRIDENT CORRUGATED FLEX SAE J2006 MARINE WET EXHAUST HOSE (HARD WALL WITH WIRE) - 2 Feet $15.00
BUA70HSS36C
BUCK HOSE CLAMPS S/S FROM 1 13/16" TO 2 3/4" 4 $8.00

Danny Jensen
A BOA VIDA
Hull 972

Sent from my iPhone

[Warren Updike]

Thanks, Danny and Jeff. This message just went into my Future Projects folder. At 22 going on 23 years, I guess it's time for a new muffler.