Increasing the throttling would increase the pressure reading.
On fully closing the valve, very high pressure beyond safe working pressure would cause motor's bimetal over load relay to trip (provided it is set properly).
If overload relay is set wrongly at higher value, then the weakest path of oil would break. Pipe fitting may leak or brust. If this does not happen, then there would be risk of burning or damage to motor winding.
Always Relief Valve is provided in the hydraulic circuit. It behaves like overload relay and ensure the pressure build up is limited to the set value on the Relief Valve.