one side of my captain choice exhaust is not closing - help please
 

Within the last few days I have noticed that my engine sounds louder when firing it up and cruising. I have captain choice exhaust and normally leave it 'closed', where the exhaust goes out the leg. I just realized that one side is going up the top exhaust while the other is going down the leg. I tried to switch the exhaust back and forth many times, but no change. In each attempt the solenoid is turning the valve/switch on top of each y-pipe. It seems like the flapper inside the one side is either broken, or just not closing all the way.

Any advice on how to fix? Are the flappers typically replaceable, or will I need a new y-pipe?


Thanks

Is this the air operated Mercruser type. If it is remove the air line and put a drop of dish soap in and reconnect the air line. If they are electric solenoids and they are both working then you may have a broken flapper. My SCARAB used to spit them out at least one a year.

Motor is a 454 Merc, but not sure if the captain exhaust is factory or aftermarket. Either way it is electronic solenoid. Both are working, just that one side is not 'closing' even though the solenoid is switching the flapper. Sounds like a flapper is gone - are these replacable, or do I need a new diverter?

Thanks

They usually just bolt onto the shaft. I always kept a spare with extra bolts.

Anyone have recommendations on how to remove the y pipe diverter. I loosened all the clamps around the rubber exhaust joiners, but it doesn't budge. Is it best to keep working it, or is it best to remove the riser. My concern is that I see lots of rust where the riser bolts attach to the manifold - I concerned that the bolts are rusted and may snap.

Any suggestions?

Thanks

The rubber glues itself to the pipes. Take a long skinny screwdriver and slide it between the rubber and the pipe and work your way around the pipe. They will come loose. I could change my flappers by reaching up the tail pipe. Did you try that?

Well, I wiggled, wiggled, wiggled! Eventually got the diverter out. The flapper was totally gone, along with the 2 bolts. Took it to the local merc shop and they confirmed it is the stock merc cast iron diverter. But looking at the PC he could not find this exact one - mine has a vertical shaft, where most Merc diverters are horizontal shaft. Anyway, he gave me a surplus flapper he had, which was oval shaped and bigger in all diameters. Spend about 1.5 hrs on the flapper with my grinder, and eventually made a perfect fit. Put it all back together and works perfect. Oh, I put locktite on the new bolts - hopefully that will prevent it from happening again soon. A job I was expecting to take an hour or so ending up taking the whole day (like usual I guess)

BTW - I think in the future I will try to install the flapper from the back exhaust pipe. I didn't do it this time cause I needed the diverter off to take to shop to hopefully find the proper flapper. Though I made a 2nd custom flapper too, so next time it is being installed from the pipe.

Thanks

The problem is that locktight doesn't work well because the heat from the exhaust burns it up. Sometimes You can stake the back side of the bolts where they extend through the shaft.

You are not supposed run the diverters closed above I think 3000rpms. It may be even less than that.

Really? I never heard of that - what is the issue if I do keep them closed at 4200+ rpm? I generally keep them closed all the time since we live on a small lake and when open the boat can be heard from all the house along the lake. I think there are also some laws that if I keep them open I may have some issues with the local cops.

Hopefully the only issue keeping them closed is the flappers eventually falling off - I can always replace them.

Thanks

It ruins the diverters. They are not designed to handle that much exhaust pressure.

A single engine stock 454 with wet exhaust is not over any legal decibel limits.

+1 with Griff. I believe it may also state the same in the owners manual.

I've been told to never to run over 3k rpms as well.

Usually the noise limit is measured at idle, not while on plane. Don't know your lake, but testing is always done at idle and where I boat I can be as loud as I want once on plane. Example - Turndowns are the preferred method of noise restriction and once on plane, the exhaust tips are out of the water making the boat pretty loud.

There is some confusion over whether switchable exhaust is even legal in NY, but personally, Ive never had a problem.

Yep, 3K RPMs is the max.

Am I the only one that thinks it would be a blessing for this to fail? This is one of the first things I ripped out of our boat.

A good friend of mine runs his closed all the time at high RPM to keep his wife happy. I keep telling him he's asking for trouble down the road. He refused to,listen to me. I found his owners manual and showed it to him in print.

Buck