If a head soaked engine won't start because of fuel vaporisation, what is the recommended action?

The recommended action when facing a head-soaked engine that won’t start due to fuel vaporization is to operate the prime pump while keeping the mixture in idle cut-off to help purge the vapor from the fuel system. This method is effective because when a head-soaked engine is subjected to high temperatures, it can lead to vapor forming in the fuel lines or injector nozzles, preventing liquid fuel from reaching the cylinders. By using the prime pump in this manner, you facilitate the introduction of unvaporized fuel into the system, thus promoting a more successful engine start.

Utilizing the prime pump helps to ensure that fresh fuel is drawn into the system, displacing any vapor that might be present. Keeping the mixture in idle cut-off assists in preventing flooding the cylinders while still allowing vapor to be purged from the lines.

The other options do not address the root cause of the vaporization effectively. Allowing the engine to cool might help in the long run, but it does not provide an immediate solution for starting. Using starter fluid can introduce its own set of risks and is generally not recommended as it can damage engine components. Increasing throttle to full open may cause air-fuel mixture issues and does not tackle the vaporization problem directly. Thus