Cobaltchat.com

That's normal. They don't come out 100% the cc exit. They don't get sealed off at the diverter. Some will always go past it.

BB I'm talking about the difference between two styles of exhaust bellows.

Factory is sealed/clamped on both ends which forces all the exhaust through the drive:
The style that's on my boat is only clamped on one end. This allows some of the exhaust (and noise) to bypass around the drive:

thunder550 wrote: Sat Apr 28, 2018 8:07 am BB I'm talking about the difference between two styles of exhaust bellows.

Factory is sealed/clamped on both ends which forces all the exhaust through the drive:

s-l300.jpg

The style that's on my boat is only clamped on one end. This allows some of the exhaust (and noise) to bypass around the drive:

Exhaust-Tube-Bellow-Mercruiser-1-MR-Alpha-One-Gen-II-Bravo-Replace-78458A1.jpg

Oh my bad. Thanks for correcting the old man. My boat has the bottom one.

So Ive Googled and have not found any definitive answer so I thought I'd throw it out here.

In a video someone posted somewhere a salesman said you should never turn a CC on or off while underway. Then I saw it on another forum where someone posted the same thing.

I've turned mine off and on while underway several times. I like it. A lot! My bride not so much. I told her it's purpose is to cool the drive so I have to flip it on every now and then and she's fine with that.. So I do it all the time. Usually at strategic places like passing other boats, campgrounds or just out in the middle.

I noticed yesterday while cruising at about 3,000 RPMs, when Is flip it off I could almost feel the boat... hesitate or slow down a fraction? Hmmm. Is that my imagination?

Maybe. But this morning I've looked all over the innerwebs and haven't found anything on the topic.

What do y'all say?

Our sales person said the same thing - only open or close the CC at idle. I don't see an issue turning it on while underway. His thinking, and Mr. Nauti agreed, was that when you close it while underway you are asking a small solenoid to close a valve while the exhaust leaving the engine is pushing against it. Who knows if it makes a difference, may be over thinking it, but IMO once its turned on it should just stay on!

I can honestly say I flipped at will

The solenoid doesn't close anything. There are springs inside that take care of that. The solenoid pulls the flappers open and holds them that way. When the switch is turned off, power is cut to the solenoid and the springs take over to close the shutters. I've never heard not to open or close them while running, no idea why that would cause any issues. I believe that some boats are even equipped with an RPM switch that automatically opens the exhaust at a certain RPM.

CC still uses the diverter or "Y" when in use.

That is 2 exhaust points now. The conflict is for as you guys stated operating a solenoid do go back and seal partially and go through the bottom suddenly with added exhaust pressure. It does strain the solonoid as the amp load gets high.

On a performance note.. the only engine systems in Cobalt that force you to have CC are mercs 500 efi and up. ( yes my fav) and most of those system where full time out the sides like a Chaparrel uses. Geeze.. never to be quiet but they where partially summerged at rest and 5mph

Merc would recommend using through hull at 2500 rpms and higher as did dealers for warranty?

Now how do they know if you didn't right?

I've done it at cruise speed and never worried about it. ( Gotta ask for a Boozer right?)
But I'm referring to WOT switching ...I'm thinking at high rpms it's just mean to do that to any engine.

So.. play it safe avoid wearing out your Corsa..
but remember one very import thing...

Let it be Loud!!

thunder550 wrote: Sat Apr 28, 2018 12:12 pm The solenoid doesn't close anything. There are springs inside that take care of that. The solenoid pulls the flappers open and holds them that way. I've never heard not to open or close them while running, no idea why that would cause any issues. I believe that some boats are even equipped with an RPM switch that automatically opens the exhaust at a certain RPM.

My friend has a 35 fountains with that feature.. apparently they did away with the auto open he said because it failed miserbley on the early Corsa solenoid. .. pretty slick idea though

I may be wrong ... but I believe the only requirement is not to engage /disengage above 3,000 rpm.
99% sure that's what I read in my corsa manual and 100% sure that's what I read on a few different boards over the years .

Found it This is for the 82501-CBI1 kit for the Volvo 8.1 OFST twin div kit

Thanks Eric!

As much value as I've received from this board ... It's nice to be able to contribute a little myself

Eric55AMG wrote: Sat Apr 28, 2018 8:53 pm As much value as I've received from this board ... It's nice to be able to contribute a little myself

Nice it's all good. We like seeing and hearing your boat too

Big Block Power wrote: Sat Apr 28, 2018 9:14 pm

Eric55AMG wrote: Sat Apr 28, 2018 8:53 pm As much value as I've received from this board ... It's nice to be able to contribute a little myself

Nice it's all good. We like seeing and hearing your boat too

Yeah! Nice seeing it in print. I see a CC video thread coming!