just replaced head gaskets, spun the motor, plugs out to get compression reading on all 4 cyl. checked 2 cyl nothing for the nexted. motor spins but not enough to engage bendix. checked voltage at motor when solenoid is engaged reading only 6.4 volts. check power to batteries when starter is turning have 12.60 volts. did a brush to the motor go, or solonoid gone. the bendix part moves up and freely, motor does not spin quick. <br /> please help