Nothing is loose under the covers, some can be removed without removing the engine but in most cases it's easier to track down the problem, a step at a time removing the powerhead to ck the w/tube grommet, then the exhaust covers and then the water jacket cover if is nessicary
Wow Laddies.... i sure have to admit that you know your stuff! I looked at the exhaust plate and figured that it could be removed without removing the whole powerhead.
Be careful of how hard you twist on those 1/4-20 manifold bolts. If any of them require more than "gentle" force, stop and first heat up the area with a propane torch and they should come loose.
Otherwise you may break bolts and that repair is No Fun!!
Spread a thin coating of Permatex #3 Aviation-Type non-hardening gasket dressing on each bolt when you put it back together, and they'll always come out if needed in the future. Most auto parts stores carry small bottles of #3 with an applicator brush.
We have plenty of Salty Dogs out here in the Beautiful Pacific Northwest!!!
You learn to use the Mercury Wrench (lotsa heat) so you don't have to replace all the nasty broken bolts with Heli-Coils!
It also makes you appreciate it when you get in a fresh-water motor, so easy to work on. Guys in the Midwest etc with all the lakes and large bodies of fresh water have it made!