[C320-list] Aqualift muffler drain problem

[Jeff Hare]

Hi Larry,

I have not done this myself.  But this is what I think I would generally
attempt.  

1. Use a Dremel with coarse sanding drum to clean up and widen the hole in
the side of the muffler enough that when you tap the new hole, there is a
decently thick layer of epoxy all around for the threads to bite into.  If
you really want it to hold well, find a tap large enough to cut threads into
this larger hole for the epoxy to bind to, but maybe that's overkill.  I'd
do it if I had a tap on hand that size.  (Harbor Freight has tap sets that
are inexpensive and will do the trick).

2. Use the Dremel with a flap disk or something to roughen up the outside
surface around the hole as well. If it's gelcoat, you need to be sure it's
roughed up well.

3. With pencil, Draw a large X on the side of the muffler over the center of
the hole so that after you fill it, you'll be able extend the lines back to
mark the original center of the hole and know where to drill the small pilot
and then the larger hole to be tapped.

4. JB Weld "MarineWeld" or Marine Tex should do the trick. I think they're
putty stick versions, they'll be thick and will let you form it and press it
into the hole and overlap the outside surface area you sanded by about a
half inch all around, but be sure you can still see the lines you drew so
you can extend them back to find the center of the hole again. You should
try to drill the new drain in the same place as the old one.

5. Once fully cured, block sand the outside surface of the epoxy so you have
a flat surface where the drain will thread in and seat.

If you want to test this process out ahead of time, just take a piece of
wood, drill a hole about the same size and pack it with Marine
Tex/MarineWeld (overlap the outside surface a bit also for strength). After
cured, drill a hole and tap it to fit the drain threads and see how that
does. I would not recommend trying to just wrap the drain body with Marine
Tex and "glue" it back in the muffler. Doing that could become a disaster if
it didn't work perfectly and it's useful to be able to remove the valve body
if needed.  Might consider soaking/cleaning up/lubing the old valve or
replacing it at the same time. This way you can do the project right and
never think about it again.

-Jeff Hare

-----Original Message-----
From: C320-list <c320-list-bounces at lists.catalina320.com> On Behalf Of
windswept at stx.rr.com
Sent: Saturday, January 15, 2022 12:10 PM
To: C320-List at Catalina320.com
Subject: [C320-list] Aqualift muffler drain problem

Hi All,

 

Has anyone repaired the aqualift muffler where the drain fitting screws into
the side of the muffler just above the bottom?  On WindSwept mine developed
an intermittent small leak and I decided to replace the fitting.  When I
took the fitting out the male threads were badly corroded.  Seemed like an
easy fix but when I screwed in a new fitting it became obvious that the
female threads were in bad shape too.   So far I have not be able to get a
leak free seal even with the use of a generous amount of Teflon tape.  The
internal female threads are so bad that the fitting doesn't engage until the
fitting is almost bottomed out.  I am looking for a fix that I can make
without having to replace the muffler or take it out of the boat.  I would
like to avoid removing it if possible.  Any suggestions?

 

Larry

WindSwept C320 #246