Engine heads

Chris,
Welcome to CCfan. We always ask for pictures so if you can post some, we'd love to see the boat.

Are you sure the oil is engine oil and not trans fluid? If the trans cooler is compromised, then the oil could be coming from it. Check the trans for water which would indicate the cooler may be the problem.

Getting hoses off can be a problem even if a sealant hasn't been used. The rubber over time has a tendency to bond to the metal. Wedging something like a screwdriver between the rubber and metal and then working it around the hose seems to work.

Exhaust drains can also be a problem since they corrode into the manifold. Heat may be needed. In some severe cases, the manifold needs to be removed for better leverage or even machining the plug out. If you are winterizing the manifolds, a temporary solution is to remove the water hose from the end and then vacuum the water out. It will get the majority of the water and then get plenty of antifreeze in.

Chris - You might want to do a pressure test of water circuit in engine before spending much more time trying to get stubborn plugs out. You just need to close off input & output ports, Then fashion a air hose fitting & gage into one of them. it should hold 15 PSI.

If the block or manifolds are cracked you will know it right away.

If so, you would be better off just pulling the engine out of boat.

Good luck