* Standard engine: The 4240S typically came with a 6.6-liter John Deere 6068 engine, which produced 105 horsepower at the PTO (power take-off) shaft.
* Optional turbocharged engine: Some models were equipped with a turbocharged version of the 6068 engine, which could deliver 115 horsepower at the PTO.
Therefore, the horsepower rating of a John Deere 4240S can be 105 horsepower or 115 horsepower, depending on the engine configuration. To determine the exact horsepower of a specific tractor, you'd need to check the tractor's data plate or consult the owner's manual.