I have a 1957 Evinrude Fleetwin and I am having a hard time getting it to start. I keep pulling and pulling and I cant even get it to sputter. I checked the spark plugs for spark and they are sparking fine. I have champion CJ6 sparkplugs in it now. I also checked and I have fuel in the bowl of the carb,so I must be getting fuel. Does anybody have any advice?