***one important thing- DON'T turn the water on full blast!!!!! You'll destroy your head gasket. Like Motoman said- start the ski and let it idle. Then SLOWLY turn the water on till you see it start to piss out the side. Let it run for a bit and then turn the water off BEFORE you turn the ski off.
As for starting it on land, grab the bars and tilt the ski to the left (so the carb side is in the air). Than start it and run it for a sec to blow it out. That way you wont get dirt, mud, whatever up in the intake and through the pump.