The seven screws on each side of the pump. Start with one, skip two and tighten the third, repeat until you've gone around twice to make sure it's torqued evenly.
While your looking for a screw order a new pump. Your going to continue to have problems with the pump you have now. I've never tightened the screws on a Flojet pump. I just checked a Flojet pump I've got here and the screw were all tight.