Motor must be running to properly flush, to circulate water thru the impellar and around the engine block and out.
Never run the motor w/o a water source.
I hook mine up to muffs or ears connected to a garden hose, the double outlet style to cover both water intakes on the foot. Let it warm up and don't push it past idle.
I've never used the built in flush mode, I believe it takes an omc adapter.
It will begin to pee after a couple of seconds, probably not as hard a stream as when its in the water due to backpressure, but it will pee after a couple of seconds providing the water pump is working properly.
Let it run on the muffs for a few minutes at idle, the pee stream will warm up as the engine warms up, which is when I shut it down and move on to the other motor,
