Is the Volvo Penta D4 260 Marine Engine designed to run on unleaded fuel only?

The Volvo Penta D4 260 Marine Engine is designed to run on diesel fuel, not unleaded gasoline. This is because the D4 series is a diesel engine line, which utilizes compression ignition rather than spark ignition, which is typical for petrol engines that use unleaded fuel. Diesel engines are built to withstand higher temperatures and pressures, which contribute to their efficiency and performance in marine applications.

This distinction clarifies why the correct answer indicates that the engine does not run solely on unleaded fuel. The use of the term "unleaded" implies gasoline, which is incompatible with diesel engines like the Volvo Penta D4 260. Therefore, the proper fuel for this engine type is diesel, ensuring optimal performance and adherence to the manufacturer’s specifications.