What is vapor lock?

Vapor lock is specifically a condition that occurs when fuel inside the fuel system vaporizes due to high temperatures, which can hinder or block the flow of liquid fuel to the engine. This phenomenon typically arises when the engine or components of the fuel system become excessively hot, leading to the creation of vapor bubbles in the fuel line. When this vapor formation happens, the fuel pump may struggle to pull the vaporized fuel, resulting in a drop in fuel delivery to the engine, causing performance issues or even a complete stall.

This understanding is crucial for diagnosing and addressing fuel delivery problems in small engines, especially those used in outdoor power equipment where operating temperatures can fluctuate significantly. By managing temperatures in the fuel system and ensuring adequate cooling, the risk of vapor lock can be minimized, allowing for reliable engine performance.