Just took my Catalina 27 (with a universal m-18 motor in it) our for a cruise. It noticed a slight running sound when I started it up, went cruising for 20 mins and opened the engine compartment and a bunch of smoke was in there. I can’t see any belts rubbing or anything touching the engine that is melted. It smells like electrical or rubber type thing. I came back to the dock and killed the motor to have a look. Started it up again and running at full throttle tied to the dock and can smell it slightly but not as bad as before. Been running it for 20 mins now at the dock . Water pump has good flow. Any ideas ?