as far as im aware its 8v at the black box, the throttle switch should click when you move the throttle. and to test it remove the plug and use a multimeter set to read ohm's between terminal 1+2 and it should read close to 0 when throttle closed and nothing when open. then put the meter on terminal 2+3 and it should read nothing when the throttle's closed and on half throttle. and close to 0 when on full throttle. then using the miltimeter set to volts you should have bottery voltage on terminals 1+3 of the plug and nothing on 2.
hope this helps.