Disconnect the connector and use a dedicated connector to connect to the vehicle battery supply leads as illustrated.Make the connections as shown in the diagram (bridge pin 2 with pin 4) and supply the engine at the battery leads (use the feeder).If the motor rotates at maximum speed in these conditions then it is working properly and the defect could be due to the regulator built into the motor support. Proceed with replacing the motor indicating that the regulator is defective on the chart.