Awesome boat! How much did you pay for it if you don't mind?
Just don't use the engine to get out of a really shallow spot, paddle or get out & push.
The one hose that comes off the reduction nozzle is going to the inside back of the boat is a water siphon that will suck water out of the hull. the other line that comes off the middle part of the pump is to force water in and cool the motor.
As stated before, it's a Yamaha motor, really only the carb & intake is diff for the wetjet jetski models (it's a 46mm carb) and they are usually gold colored. It's known as a '61x' motor, 701cc. You have single carb 61x cases, 61x cylinder, 61x head. Ebox is basically the same for 2 cylinder yamaha 650cc, 701cc, 760cc motors.
Most people here would agree to remove the stock oil tank and injection on the front cover of the motor (get or make a blockoff plate) and mix the oil yourself. Very easy to do. 1 less thing to fail and kill your engine.
Hope that helps.