An engine start control system comprising: a manual starter which allows manual rotation of a crankshaft of an engine; a generator which operates in association with rotation of the crankshaft; an electronic fuel injector which feeds a fuel to the engine; an engine control device which operates using electric power generated by the generator, and controls the electronic fuel injector; a pressure detection section which detects pressure in an intake pipe on the downstream side of a throttle valve of the engine; and an air regulator which feeds air to the intake pipe on the downstream side of the throttle valve, the engine control device comprising: a maximum value detection section which detects, in the process of starting by the manual starter, a maximum value of pressure in the intake pipe detected by the pressure detection section, within a predetermined range of crank angle after activation of the engine control device; an idling control section which controls the air regulator to thereby keep the idling engine speed at a specified value; and a correction section which corrects the maximum value of pressure in the intake pipe detected by the maximum value detection section to the atmospheric pressure, based on a control volume of the air regulator made by the idling control section. a manual starter which allows manual rotation of a crankshaft of an engine; a generator which operates in association with rotation of the crankshaft; an electronic fuel injector which feeds a fuel to the engine; an engine control device which operates using electric power generated by the generator, and controls the electronic fuel injector; a pressure detection section which detects pressure in an intake pipe on the downstream side of a throttle valve of the engine; and an air regulator which feeds air to the intake pipe on the downstream side of the throttle valve, the engine control device comprising: a maximum value detection section which detects, in the process of starting by the manual starter, a maximum value of pressure in the intake pipe detected by the pressure detection section, within a predetermined range of crank angle after activation of the engine control device; an idling control section which controls the air regulator to thereby keep the idling engine speed at a specified value; and a correction section which corrects the maximum value of pressure in the intake pipe detected by the maximum value detection section to the atmospheric pressure, based on a control volume of the air regulator made by the idling control section. a maximum value detection section which detects, in the process of starting by the manual starter, a maximum value of pressure in the intake pipe detected by the pressure detection section, within a predetermined range of crank angle after activation of the engine control device; an idling control section which controls the air regulator to thereby keep the idling engine speed at a specified value; and a correction section which corrects the maximum value of pressure in the intake pipe detected by the maximum value detection section to the atmospheric pressure, based on a control volume of the air regulator made by the idling control section.