Air coming out of engine near turbo area when shut down.

[Advantage]

I have a 2007 Formula 400SS with Volvo Penta D6-350s. I noticed something while performing end of the year maintenance. I believe it's been happening for some time. Boat has run great all season with no loss in RPMs or overall performance.

So, here's the question. I am attaching a video. Oops, it won't let me attach videos here. When I shut off the port engine, there's the sound of air coming out of the engine near the turbo area. It last between 5-10 seconds every time. I haven't measured turbo pressure but will try that tomorrow. My starboard engine does not do this.

Thoughts from anyone?

 

[spannerman]

The turbo provides no boost at idle, it could be the seawater filling up the down pipe as the exhaust flow has now stopped and is pushing the air out somewhere.