MarkMontereyBay (11/22/2012)
Put the starter on the floor. Attach the black/neg jumper cable to the starter case then put your foot on the starter to hold it from jumping off the floor and touch the red/positive cable to the starter positive stud. I have been burned by this test in the past. The starter turns fine with the jumper cables but put it back on the motor and it falls flat under a load. There is a on-the-car starter amperage draw test that is a better way to test it but you need an inductive amp gauge or one of the older test meters that has a specific positive link (shunt?) that is connected to the positive battery terminal. Then you crank the engine and read the amount of amperage it takes to turn the starter motor. There used to be specs for this, I seem to remember something like more than 200amps meant the starter was weak. I still have an old Fox Valley test meter that has one but haven't used it in decades. Maybe some the older mechanics here can explain that one better. Way back when cars had the fire hazard true amp gauges instead of voltmeters, it was easier to see what the amp loads were.The old timer auto electrician test is to clamp starter in vyce and place piece of hardwood timber between gear and bench, with battery cables connected to starter, jam neg cable to batteryy to get it spinning and lever timber up into gear causing load on starter, there will be sawdust etc flying around but replicates decent load on system. 