This modification involves removing the factory-installed oil injection system from a Mercury outboard motor and switching to a pre-mixed fuel and oil solution. In a typical setup, the original system automatically mixes oil with the gasoline before it enters the engine. A deletion kit provides the necessary components to bypass this automatic process, requiring the operator to manually mix the oil and fuel at a specified ratio before fueling the engine.
The rationale behind this alteration often stems from concerns about the reliability of older oil injection systems. Malfunctions in these systems can lead to either insufficient lubrication, causing engine damage, or excessive oil consumption, resulting in fouled spark plugs and reduced performance. Proponents argue that the pre-mix method offers a more direct and controllable approach to ensuring proper engine lubrication, potentially extending engine life and preventing costly repairs. Historically, as these oil injection systems age, the likelihood of failure increases, prompting many boat owners to consider this preventive measure.