Sounds like it's prefered that it be located after the filter and closer to the motor.
http://forums.bateau2.com/viewtopic.php?f=10&t=19339
I had some clogging issues with junk in the fuel tank in my 67 Wellcraft and it helped to have the primer bulb after the filter as the filter caught the stuff which I would think could affect the bulb if you get junk in it possibly causing the valve to get stuck?