What Causes Difficulty in Starting a Warm Pull-Start Gasoline Engine?

[LeDeclan]

Difficulty in starting a warm engine is primarily caused by excessive carbon buildup in the throttle body, idle air control valve, intake manifold, intake valves, and combustion chamber. When carbon deposits and dirt accumulate excessively in the intake manifold, the cross-sectional area of the air passage changes, preventing the control unit from precisely regulating the idle air intake. This results in an overly rich or lean air-fuel mixture, leading to abnormal combustion, engine shaking after startup, or even failure to start. Below are other potential causes: 1. Minor fuel injector leakage: Fuel may seep into the combustion chamber after the engine is turned off, causing an overly rich mixture during subsequent startups and making it difficult to start. 2. Damaged charcoal canister: If the solenoid valve remains open, the air-fuel mixture in the intake manifold will stay enriched, leading to an overly rich mixture when the engine is warm and making it harder to start.