ox 66 vst tank fuel pump question

[goodride]

On the electric pump, in the vst tank the diagrams show a round spacer and o ring at the top of the pump.
we just got a boat with a 250 and it will run for less than a minute and stall...we went to check the screen on the pump in the vst and noticed no spacer or o ring....will this cause the motor to stall after starting fine and running for about 45 seconds??

[boats.net]

Without the oring it will not hold fuel pressure or a loss of pressure.