In the prestart phase the mixture should be richer. By applying 1.5 Volt = 1.5/200 = 7.5 mA the mixture is richer, this acts like a choke. If the voltage you measured is lower then the mixture shouldn't be too rich as in your case. The only conclusion is that the current is not max negative or positive and the motor starts around the basic adjustment. It looks like the controler is not the cause. Although you have to electrically disconnect the actuator (= pressure adjuster) to be sure.