A friend gave me an 91 Baretta with a OMC Cobra 3.0 I/O. Starts and runs great. Problem is water in the oil and water running out of flywheel housing. No water out of exhaust. Changed out the oil and ran for a few minutes, 3 or 4, and no new water in oil. Noticed gasket in flywheel housing was pushed out(blown) is this from exhaust pressure? I'm not a mechanic or especially familiar with boat engine problems, but I can usually figure things out with some insight from those that are. Thanks in advance.