[Mrmerlin]

the other part that should also be replaced is the fuel pump check valve always use new sealing washers for this operation,
you need three of them.

Once the engine is hot the fuel will vaporiz if there isnt enough pressure in the lines.

Also if the check valve is bad then fuel will return to the tank from pressure in the lines,
thus creating and air pocket in the line so it takes a bit of cranking for the fuel to refill the lines.

When the engine cools the vaporized fuel re condenses and the pressure in the tank forces the fuel back into the line so to effectively refill portions of the line so a cold start happens quickly if the WUR is functioning properly