Hot Start 1950 Merc

[drolston]

The most common causes of not starting when hot are (1) vapor lock and (2) coil. With an electric fuel pump, it is pretty safe to say that #1 is not your problem. So, check the coil. Disconnect any spark plug wire and hold the tip of the wire close to any ground. When cranking you should see a white to blue spark that will jump half an inch. If no spark or yellow and weak, try a new or rebuilt coil.