There is an owner manual for a 4015 in the parts and manuals section. It includes a wiring diagram and exploded views of most of the areas of the machine. I don't know what difference there is between the 4015 and 4016 - if it isn't much, you might like to subscribe and download that manual.
The owner manual includes a troubleshooting guide, and it does not mention shutting the machine down with the cutter clutch engaged as a reason for the engine not to start subsequently. I would be inclined to check for mechanical faults first - such as whether the cutter clutch is free when the machine is parked. Please disconnect the battery cable and the spark plug before you make this check. I know that is obvious, but people sometimes forget.
