89 xj starter issues

I have had my Jeep for about 4 years and I have gone through 4 starters. I was wondering what the problem might be? I’m guessing it has to be something electrical. Maybe too many amps going to the starter?

What part of these starters is failing?

I’m not sure exactly… I would take my starter to schucks, have them test it and it would fail. I would always just replace the entire starter.

That is kind of strange alright. Unless the starter motor is being slowed down by the engine not turning over correctly the current should be ok. You can have a current check done to see if the motor is drawing excessive current while it is mounted in the vehicle and it would be a a good first step I think. You might also check to see if there is a problem with the battery lead to the starter. You could check the voltage on the lead between the positive battery post and the starter connection. I would think there should be less than .2 volts across the lead when cranking the engine if the wire is ok.