Seems to me that since you are using a known
good strong battery that the trouble is going
to be with the starting system, most common
would be that the plastic pinion gear is
locking into the ring gear on the flywheel,
usually caused by a worn or broken pinion
gear, take the plate off that covers the starter, do not remove the starter , and see
if this is the case. If not, then you could
havc two bad starters.
