What is vapor lock and how can it be prevented?

What is vapor lock and how can it be prevented?

• A. Vapor lock is fuel vaporization causing flow interruption; prevented by proper routing, anti-vapor lines, maintaining fuel temperature, not letting fuel get hot.
• B. Vapor lock refers to air lock in the engine's intake manifold.
• C. Vapor lock is a temporary water contamination fix.
• D. Vapor lock is when oil vaporizes in crankcase.

Answer: (A)

Vapor lock happens when fuel in the lines boils and forms vapor pockets, so the pump ends up moving gas instead of liquid. Those vapor bubbles interrupt the flow, causing a loss of fuel to the engine and potential engine stoppage. The best way to prevent it is to keep fuel from getting hot enough to boil and to design the system so the fuel isn’t heated in transit. That means routing fuel lines away from heat sources, insulating or shielding lines, using anti-vapor lines, and maintaining the fuel temperature within safe limits (not letting it get excessively hot). This keeps the fuel in liquid form so the pump can deliver a steady, continuous flow. Vapor lock is not about air in the intake, water contamination fixes, or oil vapor in the crankcase.

Vapor lock happens when fuel in the lines boils and forms vapor pockets, so the pump ends up moving gas instead of liquid. Those vapor bubbles interrupt the flow, causing a loss of fuel to the engine and potential engine stoppage. The best way to prevent it is to keep fuel from getting hot enough to boil and to design the system so the fuel isn’t heated in transit. That means routing fuel lines away from heat sources, insulating or shielding lines, using anti-vapor lines, and maintaining the fuel temperature within safe limits (not letting it get excessively hot). This keeps the fuel in liquid form so the pump can deliver a steady, continuous flow. Vapor lock is not about air in the intake, water contamination fixes, or oil vapor in the crankcase.