I have an '72 65hp Evinrude with a jet on a 16' roughneck and the motor runs very strong. When it is marginally warm, it will die off suddenly, acting like it runs out of fuel, but when I try to start it again it acts immediatly flooded and cannot be started for at least 30 min. I have taken to "checklist starting" I pump the bulb every time I start it, even warm, and set the fast idle up and have my hand on the choke. When I do this if it starts to die I give it a quick pull on the choke it runs fine, but if I forget one thing and it dies it will not start again. Any ideas on what is going on?