Which of the following is NOT a maintenance tip for engines?

Ignoring battery maintenance is not a wise choice when it comes to taking care of an engine. Proper engine maintenance practices are crucial for optimal performance and longevity. Maintaining the battery, which includes checking its charge and ensuring the terminals are clean and secure, helps prevent issues such as starting failures or electrical problems. The other options highlight essential maintenance tips: keeping the engine well-tuned promotes efficient operation, regularly checking oil levels ensures that the engine stays lubricated, and changing oil frequently prevents sludge buildup and protects engine components. Together, these practices contribute to a well-functioning engine, while neglecting battery maintenance can lead to breakdowns and more significant issues down the line.