When you reinstall the needle & seat assemblies lube the o rings, then screw them in deep enough that the nut barely has anything to grab... That way when you start the engine you'll know the fuel level should be low.... So, with the sight plug out and a screwdriver & 5/8 wrench you can slowly raise the level... If your careful you can do it with the engine running, back the lock screw off slightly so fuel weeps but not so much that it becomes a serious leak... Turn the nut one flat & snug the screw... Let the fuel level stabilize... Repeat till the fuel level is at the point it just trickles from the sight plug hole....