i went for a ride and the lotus just decided to stop i noticed i had no fuel in the filter unhooked the fuel line cranked the engine nothing no fuel
my first thought was the membrane is torn
but that wasn’t it it was a one way valve that didn’t close so i took it all apart
cleaned it up tested and now it’s ok must have been some dirt preventing it to close
there is a filter inside the pump in the shop manual there no inline filter before the pump mine is just before the carburetor the one way valve is in the last picture
i cleaned it with carburetor cleaner after i put it in hot water with dishwashing liquids move the valve open closed rinsed it and now they work fine so if your pump stops working just take it apart it could be an easy fix