Re: Prealpha, how to check shutters?
After what I'm going to say, you'll probably do what the others have suggested, rather than check your shutters...
You'll need to pull your exhaust risers, pull the rubber exhaust bellows (on the ypipe), then comes the hard part, you need to pull the pipes from the exhaust separator. With the engine in the way this will probably be impossible unless you're really lucky, or had everything apart recently. These bolts are also hex drive which makes this even harder. You'll probably then need to pull the out drive, pull the engine and pull the exhaust separator from the gimbal housing. At this point you've basically taken your boat apart.
Once you have the pipes off the exhaust separator you can check your shutters... At this point, since you've gone through all this work, you might as well replace them (if they're even there anymore).