vst fuel pump wont seat

[22angler]

Ok guys this has got to be simple but I can't see it. I am replacing my electric fuel pump in my ox66 200hp. The replacement is oem and identical to the old one. When I put the fp in the top of the vst, I can't get the top to seat on the tank body. The fp side comes up about an eigth short. If I remove the filter on the fp all seats well. What am I missing? Does the fuel collar go on before the plate or before? Help I'm about to run it without the filter.

[boats.net]

May not have O-ring installed correctly on top of pump.

[22angler]

Large o-ring or small one over the nozzle? Both are seated

[boats.net]

Try putting oring on nozzle of pump then install pump.