Fuel Seperator Replacement

It is time for me to replace my fuel seperator according to the manual (100hrs.) I am a relatively new boat owner so I apologoze if this questions is mundane or routine. I replaced my oil filter a couple weeks back and was wondering if I should expect the same when I replace the fuel seperator. Also, should I expect fuel to pour out when I unsrew the seperator or is there some kind of stopage? Anybody with a heads up would be greatly appreciated.

just like the oil filter, fill it with fuel first, better start up