[C320-list] Aqua lift mufffer

[Chris Burti]

Danny,
Great write-up...I'd like to use it for a Mainsheet article with your
permission. Any pictures available?

Thanks,
Chris Burti
C-320 IA Technical Editor
Commitment, #867

On Wed, Aug 12, 2015 at 9:45 AM, danny jensen <danny at jensenshouse.com>
wrote:

> I have commented on this subject before so I hope you all don't mind my
> re-post on this subject. My impression is that mufflers need to be replaced
> proactively every 10 years along with mixing elbows. This is cheap
> insurance because you will float your floorboards and get soot inside your
> boat. It is ugly. Just pay the $375 for a new muffler and save yourself the
> aggravation.
>
> 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... at 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
>
>
>
>
>


-- 
Chris Burti
Farmville, NC