Engine Hard Starting After Days Of Rest

You have to use a "vane type " electric pump as a primer pump. I have a little one from Mr.Gasket on two of my Darts, mounted in the back on the frame rail with a sheet metal cover fabbed over them. After several days sitting I turn the switch on, hit the pump switch and count to 20 and then shut it off. Starts just like I had driven it the day before. I never use it except to prime the carb. No indication that it creates any undo restriction with the mechanical pump when it's off, but these are slightly warmed over street engines, not high horsepower or big displacement engines.