won't turn over

[98gtlights]

2000 7.3 checked batteries connections, pulled starter and tested. Checks out ok. With the starter pulled and hooked up it wants to engage but won't turn engine. I am at a loss.

[calfarley1]

Use a DVOM ond put it on each battery as someone tries to crank it and watch the voltage drop. If it drops below 8 volts either the battery is bad or the starter could be pulling to many amps when trying to turn the motor over.