Gas can get into the oil of a small engine due to several common issues. One primary cause is a stuck or malfunctioning carburetor float, which can allow fuel to overflow and leak into the crankcase. Additionally, a worn or damaged fuel pump diaphragm may permit fuel to seep into the engine oil. Another possibility is a leaky or improperly sealed fuel injector in engines with fuel injection systems. Moreover, frequent short trips that don’t allow the engine to reach its full operating temperature can prevent fuel from fully vaporizing, leading to the accumulation of oil. Lastly, a faulty or worn-out piston ring can allow unburned fuel to bypass the combustion chamber and mix with the oil. Each of these issues can result in a dilution of the oil, reducing its effectiveness and potentially causing damage to the engine.