I have a side by side 35 not a 47, but the relationship of engines, transoms, and exhaust should be the same. I have the silent choice option, there are internal flappers up in the exhaust pipe and the Salisbury style flappers on the tails, all factory set up, never any problem. My 35 has a very high X, your triple engine boat should have the outer engines up there pretty well I would think. Do you have the internal flappers up in the pipes? Have you tried Fountain, or maybe Brian Forehand @ Marker 17 for some thoughts.

Another thought, In the pipes there are some small reversion baffles, lack of right name here, that are there to stop the water from creeping back up the pipe, have seen some talk on here that sometimes they break loose and exit. Might be something to look for.

Yes, I think they are called dams. Check to make sure they are still there.

Also make sure you have no exhaust leaks. Any leak will promote reversion especially at the header/head. It's doubtful that's the problem since it's on both motors and same cylinders on both but you need to rule out any leaks.

I do not have the internal flappers in the pipes any longer because my tails are now dry to the very end and the water is exiting right at the tip, not inside the pipe and running out. The other "baffles" you are referring to are called "reversion cones" and they are all intact. I'm removing the SS flappers and putting back the black rubber ones and I will see what happens. We have one more run of the season this weekend and then I will re-pull the headers again and see if I am still seeing the water intrusion. This will hopefully rule out or rule in the SS flappers.

I can't help but believe that it's something simple that we're missing. 525s with basically dry tails should not be walking water that far up the pipe. I'm anxiously waiting to hear how things go this weekend. Hopefully without issue as I know you've stayed on top of everything with those motors. Hoping for the best.

All of my header to tailpipe connections were bonded with gaskets and Ultra Black RTV to completely seal those connections. Headers were installed with all new gaskets and torqued to Merc. spec. Could there be a leak, sure, but I highly doubt it. I have also ruled out leaks in the headers themselves as I've pressure tested them all extensively.

Couldn't agree with you more!! Thats why I was so surprised to see it.. I thought I solved that problem for sure with the dry tails..

Call David Rank at CMI , tell him you want some reversion cones made to fit between the header & tail. If he doesn't know what your taking about have him call me. The problem you and other people have can be two fold. If you boat in cold water, the tails will condensate, and the pulsing from the exhaust at idle will walk water up the outer inside of the tailpipe Or extended idle periods.. What I would always tell people to do if they had to idle for any extended periods, was to put that motor in neutral and rev it up a bit to clear it out. I have tested with success using mufflers to change exhaust pulsing, and elevating water walking up the tails. But reversion cones work too. Cheapest way is to just clear it out every so often.

not 100% sure but I thought I read a thread somewhere about reversion and it ended up being intake or head gasket issue.

I spoke to David yesterday actually. CMI made me the dry tails I've been referring to and David was the one that helped me with them. The tails already have reversion cones in them right at the flange. Are you saying to put something else between the collector flange and the tailpipe flange like a small section of pipe that houses another reversion cone or were you assuming that my tails didn't already have them and were suggesting I add them?