As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ON FIRST START ATTEMPT ON LEFT ENGINE IT HUNG START AT ABOUT 48 PERCENT N2. SUBSEQUENT ATTEMPTS HAD NO N2 ROTATION AND A STARTER VALVE LIGHT AND L STARTER EICAS MESSAGE. REMOVED AND REPLACED NR 1 ENG STARTER PER AMM MFN 774860A4, FOUND STARTER/GEARBOX COUPLING SHEARED. REPLACED SAME PER M/M. STARTED ENG, ALL CHECKS NORMAL.