Need help mercury 250 pro xs oil canister change not refilling

[6 mile]

I changed the oil tank on the motor due to the sensor going bad. I refilled it 3/4 of the way leaving about 1 inch of room at top to let it fill from motor running and cap. I ran the motor for 10 minutes it runs cool around 100F but the tank is not filling. I did not drain any of the lines so as I understand this system runs on 3-4 #pressure. I checked all the caps and fittings on tank in boat everything is tight. Is there a process I need to go thru or what are halls thoughts?

Didn't want to have to take to dealer and let it sit for three weeks before they touch it. So any advice you can give would be greatly appreciated.

Thanks in advance for you responses.

[lpugh]

Serial number is ?
Cap on motor mounted reservoir must be loose to allow air to vent in order for tank to fill

[SilverFox579]

Should have had an oil pump prime sequence done after replacing the engine reservoir, more in 3L forum (what your engine is). Engine serial number required when posting (see Announcement at top of 3L forum).

[6 mile]

Thanks guys