i just installed a mercruiser fuel water seperator on my 1996 stingray 556zp with a 3.ol mercruiser. after install boat ran rough and stalled as if starving for fuel. spun filter off and noticed it was only 1/2 full of fuel? is it like an oil filter and should you prime it with gas? pretty straightforward install so i cant see it being put in wrong. took it out and boat ran fine. thanks for any help