I could see fuel evaporation causing hard/delayed starting but it still should prime on it`s own after cranking for while. The push rod does wear and even more quickly if it is a cheap China made replacement rod. I would think if it was worn that much you would have some drive ability problems once it is running. I will say it again. The rubber lines don`t last long with the ethanol gas blends. I had hoses go bad in a year depending on the quality of the rubber.