Which maintenance procedure is suggested if the fuel starts to flow after loosening the fuel tank cap?

When fuel starts to flow after loosening the fuel tank cap, it suggests that there is a problem related to ventilation within the fuel tank. Fuel tanks are designed to maintain a certain level of pressure, and if the vent in the fuel tank cap is blocked, a vacuum can form inside the tank. This vacuum will impede the flow of fuel to the engine, causing the engine to sputter or not start at all. By loosening the cap, you allow air to enter the tank, which restores normal pressure and allows fuel to flow.

Clearing the vent in the fuel tank cap ensures that air can freely enter the tank as fuel is consumed, preventing the vacuum from forming and ensuring proper fuel delivery to the engine. This maintenance step is crucial for the overall functionality of the small engine in question.

Other procedures, such as checking the fuel filter or inspecting the fuel line for leaks, may be necessary in other contexts, but they do not directly address the issue of fuel flow being impeded by a related vacuum problem caused by a blocked vent. Replacing the fuel tank cap could be relevant if the vent was indeed faulty, but if the cap is simply blocked, clearing the vent is often sufficient for resolution.