It doesn't say it will void the warranty, it says don't use it over 2,500 RPMs. It's great for idling around yacht clubs and such. The 525 doesn't use the same Y pipe as the 496 etc. It's more of a "Z" pipe that mixes the water further downstream. I had to pay about $1,000 each for mine when I swapped out the 496 for the 525.

If you carefully read the caution statement above this "silent choice" you can understand that Mercury does not sell or install these systems on their engines as delivered. This is done by the boat builder and hence the warranty can be voided by Merc quite easily if a problem occurs from water instrusion that "Mercury" deems as being caused by that usage.

What you should probably draw from this information is that using switchable thru the hub exhaust systems on high performance racing engines is "USE AT YOUR OWN RISK".

JMO

Best Regards,
Ray @ Raylar

That page came from my 2005 353 installation manual, but the same paragraph exists in my Service Manual which is new and covers all the 525's. I disagree that it would void the warranty. Corsa, CMI and the boat manufacturers don't operate in a vacuum. Testing had to been done on these configurations otherwise Formula or whoever would be on the hook for a faulty installation and I don't see them taking on that liability.

It does not void the warranty. Ray, Mercury Racing does not install engines afaik.

After rebuilding my 525's I was so concerned about the header problems I sold the boat before they had a chance of ruining my engines.

Maybe too drastic of move.

Well I see it like this. Mercury provides the warranty and if they tell me it voids the warranty for any reversion related issues then I have no other choice than to believe them. Call them and ask and report back. Thanks for the help everyone.

My Silent Choice automatically opens at 2000 rpm's. I believe the exhaust solenoids are somehow wired to the tach feeds.

Called again today and spoke with a different rep. He said if you buy a brand new boat with factory installed switchable exhaust mercury will not warranty the motor for any water ingestion/reversion related issues. The motor will still be covered otherwise

It dosen't matter. Try to get anything covered under warranty from Merc Racing, forget it. Even if your motor blows up after 1 hour, they will find a reason why it is your or somebody elses fault.

have any of you had or heard of cmi header issues in a single engine, fresh water only, no captain choice application?

i have been told by a couple reputable high performance marine mechanics and many other people that the header problem is only in salt water and boats with staggered twin/triple boats where the forward engine has long pipes with not enough support and in rough water the pipes move a lot causing the inner header tubes to crack.