Hi, I think You need to repace it with a gasket (can later give You the part number). To achieve full 30hp power, also the timing need to be adjusted, there is a thread here on the forum about that. However, have heard that some of the engines already have the correct timing for 30 hp as factory default. As a 30hp not recomended to exceed max RPM at WOT.
I have the same engine as restricted, done plenty of NM this summer, no issues what so ever.
fun on a boat is inversely proportional to size...sort of anyway