Adding a fuel primer pump

[Avenger]

Normalization of risk. Just because you've gotten away with bad practice doesn't make it safe.

[Pascal]

Normalization of risk. Just because you've gotten away with bad practice doesn't make it safe.

I and thousands of factory installed priming pumps on quality boats “have gotten” away with it…. They re only under light pressure while priming not running

[SKYCHENEY]

Another reason to not do it that way is that pumps emulsify water which hinders filter performance when they are installed before the filter. If you are trying to polish fuel, you'll want to pull the fuel through the filter, not push it through. That's why the water separator is always on the primary. I've never seen a water separator after a fuel pump for a reason.

Maybe that's not as big of a deal on Detroits, but if you have a common rail engine then you definitely don't want to take a chance of getting any water to the injection system.