Hello J
The engine serial # would help. I will assume the engine is fuel injected. When you turn the key to on, the gauges should respond and you will hear the fuel pump run briefly. If this is not happening, start by cleaning and tightening the battery connections.
The most common problem for over heat is the water pump impeller (part # 59362T1). The engine oil cooler is located on the port (front) side of the engine which is mounted vertically. Remove the bottom water hose and feel inside the cooler. If you find small pieces of rubber, the impeller is bad. This area in the cooler also acts like the sea strainer (if there's not one in the intake hose in the engine compartment) which can catch sea weed etc. and block water flow.
Marine Mechanic
30 Year Service Tech Gas/Diesel.