A fuel conditioning system for an engine comprises a plurality of mixing vessels that include an input mixing vessel and an output mixing vessel, at least one inlet for receiving fuel and water into the input mixing vessel and at least one outlet for supplying the fuel and water from the output mixing vessel to the engine. A conduit system is arranged to transfer the fuel and water through each of the mixing vessels from the input mixing vessel to the output mixing vessel. Each of the mixing vessels comprises an internal chamber containing a plurality of nebulizing members. The nebulizing members are configured to rotate about a rotational axis extending through the internal chamber to nebulize the fuel and water therein. One or more magnets disposed in the internal chamber to attract ferromagnetic substances present in the fuel and/or water.