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355 Aft Cabin Muffler

Posted: October 2nd, 2020, 11:22 am
by chpsk8
Does anyone have any knowledge of the exhaust system on a 95 355 Aft?

Motors - 454 Crusaders

When I start the port motor for the first time after a period of "rest", the muffler is clearly empty. It takes about a minute to completely fill up and start doing it's job. When I shut the motor off, water continues to drain from the exhaust for maybe 5 minutes before stopping.
To me it sounds like even when the muffler is full that the port motor is louder than the starboard. The starboard starts a little loud, but then quickly goes almost silent.


My guess is something is broken inside the muffler. I'm wondering if it's worth cutting open to repair, or just buy a new one... Not sure what parts are actually in the muffler, maybe some form of flap that broke/cracked. which is question 2.. any idea where to get a new muffler? I'm thinking it's a Centek unit maybe? No stickers or numbers on it.

Just for clarification, there's no exhaust leak in the bilge or in the boat. The problem is internal to the muffler.
Plenty of water is flowing through the exhaust. The impeller is recent and flows strong and equal to the starboard side.

Oh and my wife says not to fix it, she likes the noise! haha! I'd like to try to improve it if posssible

Thoughts/Ideas?

Thanks

Re: 355 Aft Cabin Muffler

Posted: October 2nd, 2020, 11:40 am
by g36
I dont think I would worry about it If its not leaking water or fumes internally to the bilge. My 405 has to fill them after setting for awhile its normal to me.

Re: 355 Aft Cabin Muffler

Posted: October 2nd, 2020, 11:47 am
by bud37
I can't speak to the muffler internals, but compare the mounting angles of each side.....perhaps the one is at more down angle thereby emptying faster etc.

Re: 355 Aft Cabin Muffler

Posted: October 2nd, 2020, 3:56 pm
by bud37
Also to add, just remembered, we had one boat that had a noisy muffler on one side, it turned out to be more related to the mounting method/hanging bracket difference. The sound was being transmitted thru to the decking......big speaker... Just a little more to consider in your particular case.

Re: 355 Aft Cabin Muffler

Posted: October 2nd, 2020, 5:50 pm
by Viper
While the muffler mounting heights are likely the same for both mufflers, hose routing may differ slightly from port to starboard sides on the way from the muffler to the transom which can affect draining and acoustics. There's not much in the muffler except a baffle or an elbow inside to direct the exhaust down into the water at the bottom of the muffler. This is what muffles the exhaust noise, and this pressure pushes the water out the top (lift muffler). I've seen baffles break off but not internal elbows, anything's possible though. Having said that, in every case I've dealt with, it's been pretty obvious that something inside has let go as you can hear it being tossed around in the muffler by the exhaust and water. If you do hear this, you should replace or repair because the loose part is chewing up the inside of the case.

Re: 355 Aft Cabin Muffler

Posted: October 3rd, 2020, 10:12 am
by chpsk8
Thanks everyone, that helps me a lot. I’ll just leave it as is for now. Glad this forum exists so I can’t get opinions of experienced carver owners!