I changed the fuel lines on mine. So, the lines were empty.
Priming them was easy. Dribble a little pre-mix down the carb, and hit the starter. It fired right up, and died. A little more premix, and after about 3 times, she had fuel, and kept running.
Now on those oil lines, you can do it like this:
Unhook the oil lines, and let the oil run out, now hook it up. This gets rid of the air in the line.
Put about 1 gallon of premix in the gas tank, so that the oil pump is not necessary.
Prime it, and start it, either on the hose, or in the water, still tied to the trailer. Now, reach down, and rotate the actuator on the oil pump, like it was full throttle, and hold it open. You should soon see the oil running through the clear lines to the carbs. Once it is running clear of bubbles, you can let her go. Just to be safe, I'd shut it down, let it sit for 10 mins, and repeat, to be sure you got all the bubbles out.
Should be ready to run.
Nate