I have a 1989 30hp evinrude which I have done some work to with the help of you guys. I'm pretty sure the exhaust gaskets are leaking as I see some corrosion around the edges and around the bolt in the middle. I was wondering if it was possible to remove the exhaust plate without removing the powerhead. The bolt on the bottom corner is recessed and seems like it might be difficult to get at. Also should I not use the motor until this is corrected? What kind of damage could this cause. Thanks for any advise.