John Deere Auxiliary (Certified) Marine Engines PowerTech 4045 Series Auxiliary Drive Marine Engines 4045HF285 4045TF285 – 1800 rpm 4045TF285 – 2200 rpm PowerTech 6068 Series Auxiliary Drive Marine Engines 6068HF485 PowerTech 6090 Series Auxiliary Drive Marine Engines 6090HF485 PowerTech 6135 Series Auxiliary Drive Marine Engines 6135HF485