Manifestations may include:
(1) sudden stalling of the engine
(2) unexplained loss of power
(3) difficulty in starting the engine after a short period with the engine turned off
Risk factors for vapor lock:
(1) hot environemental temperatures with an overheated engine
(2) high altitude (with a lower boiling point)
(3) more volatile fuel (including ethanol-treated gasoline)
(4) older engine designs, especially with a low pressure mechanical pump
(5) engine with a past history of vapor lock
Vapor lock may explain some of the problems experienced in early airplanes.
