water flow from heads on 135hp evinrude crossflow

[Kracker Jack]

Replaced thermostat on this motor. Ran engine for a second with out hoses hooked to base of heads. Water didnt flow.....it pulsed out of the head. Is this odd? I realize im on the flush with muffs and the exaust housing is not full of water like it would be if in water. What do you guys think? Any links or articles concerning same issue are welcome also.