How many miles on your unit? Sounds as if the starter is failing. The sound you described likely means the starter gears are not meshing with the flywheel. That's a symptom of what omjones posted. The torque of the starter motor "throws" the Bendix gear into the flywheel gears, but if it is wearing out, sometimes it is too weak to engage. Starting the second time is a usual symptom as well. The rough start may be due to leaving the key on while you wait for the second try and thereby accumulating too much fuel. While less likely,your flywheel may have some broken teeth which would not allow a full engagement of the Bendix gear. All of that is a possibility and worth a look by you or your mechanic. If you know how to take the starter off, many of the auto parts stores can bench check it to determine if stater is getting weak. Hope some of that helps.
