I recently developed a leak on the bottom of the starboard muffler riser, where it connects to the 4 inch hose leading to the stern of the boat. Appears to be leaking through some cracks on the underside of the muffler. The bilge pump comes on every or hour or two for about 30 seconds to pump out incoming water.
I have the following questions:
Is there a way to patch, the muffler to get through the boating season? The muffler appears to be cast-iron.
Are replacement mufflers available anywhere?
If I can remove it, can it be welded?
Considering the large 4 inch hoses with hose clamps overlap the flange on the muffler, how do to get it apart? Does the engine need to be moved forward? Seems like a lot of work to do that just to remove the muffler.
Is there a fiberglass muffler alternative that I should consider?
Can the muffler replacement done safely while in the water if I plug the rear exhaust?
I replaced my mufflers with the 31 in the water. I got two plumbers plugs and wrapped them with an 1/8” or so with silicone tape. I was very nervous and made sure my bilge pumps were in good order just in case. My transome exhaust sat about half way submerged so not much head. I never had any leaks but I was at the boat everyday the exhaust was pulled apart. I pulled both cast iron mufflers and copper pipe up to the transition iron pipe on the engine riser. i replaced the cast iron mufflers with identical designed fiberglass from a local fabricator. I took a 125lbs out of the stern and the sound is only slightly different. Nowmy swim deck doesn’t drag in the water at cruise speed. I hsve both the original cast iron mufflers. If there was a way to descale them and maybe put a heat resistant coating.
If they are the origianl CC cast iron mufflers you need to replace them. I don't know of original replacements. Leaks don't get better with time. You also run the risk of CO2.
I have had Centek fabricate new mufflers with an exterior shape very similar to the old cast iron chris craft ones so they'd mount similarly.