many hard HOT restarts are from two common scenarios. One is the coil is getting hot and losing its ability to throw a hot spark...second is percolation of the carb and is often the results of todays blend of gas and high float level. Lowering the fuel level in the bowl will help prevent percolation. This can be verified after a run by observing the carb throat and inside the manifold for wet fuel and a highly concentrated fuel vapor easily seen by the eye as the fuel running down inside the throat of the carb to the hot manifold will cause this dense fuel vapor. A manifold with fuel saturation due to this temp related flooding involves opening the throttle and starting the engine..this prevent drawing extra fuel into the manifold as the low starting speed of the engine prevent fuel being drawn in as the vacuum is too low for a venturi effect. IF the engine does not start easily, and flooding is the condition, remember, every time you let up on the gas and depress it again adds fuel to the manifold through the accelerator pump on the carb.