As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
#2 ENGINE N1 ROTATION STOPPED AT 20% AND THEN ROLLED BACK. START VALVE REMAINED OPEN AFTER SECOND ATTEMPT (N1 DIDN'T MAKE IT PAST 17% ON 2ND ATTEMPT). GROUNDED - YES. OPENED FAN COWLS #2 ENG REF B737-800 AMM 71-11-02-410-806-F00 USING ALT DEACTIVATION TABLE 3, ITEM 9. FOUND METAL DEBRIS COMING FROM THE STARTER. REMOVED AND REPLACED STARTER MOTOR REF AMM 80-11-01. SERVICED STARTER REF AMM 80-11-01-610-801-F00. PERFORMED DRY MOTOR LEAK TEST REF AMM 71-00-00-700-810-F00. NO LEAKS FOUND.