[FWB]

a fuel pump will at times draw more than 10 amps, if you have two wired into the same circuit, do the math. what amp circuit are they on? as i have no idea what kind of pumps you are running and their amperage draw or their gph rating. but to run two fuel pumps why? is it the first fuel pump is underated for the application? get a good fuel pump 140gph and that should be the only pump you need to feed most motors under 700 hp. if your lines are small then putting two pumps trying to push fuel thru small lines you could have 10 pumps but you will only get as much fuel thru a small line as the line can hold. maybe the addition of the second pump just fights the small volumn of a small line and the pump self destructs like there is an obstruction.