As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AFTER #2 ENG START AND AFTER AC PANEL CONFIGURED TO START #1 ENG THE DURING #1 ENG START N2 VERY SLOW TO REACT 25% NORMAL START AFTER THAT ALL OTHER INDICATIONS NORMAL. PANEL CONFIG FOR #1 ENG START LH PACK OFF, ISO VALVE CLOSED, RH PACK AUTO, BOTH ENG BLEED SWS ON, APU BLEED SW ON. GROUNDED - YES. REMOVED AND REPLACED #1 ENGINE STARTER REF B737-900 AMM 80-11-01.