There are some commonly referred for Notes for timeout issues, I hope the following can be referred in case if helps for your case
Release 12 : ADSTRTAL.sh returns error : TIMED OUT( 100000 ): INTERRUPTED EXCEPTION (Doc ID 564536.1)
"adoafmctl.sh Stop" and "adformsctl.sh Stop" Give Timeout Errors and Both Exit With status 204 (Doc ID 1451001.1)
R12: Stopping OPMN Managed J2EE Processes Results In Timeout (Doc ID 566142.1)
Hope it helps
Can you share What is the heapsize have you given ? Did you monitor CPU/RAM utilization during startup . did you find any spike or resource issue ?
There is no users yet for this Instance. It will due for PROD next month.
Thanks Jibu and Kanda,
Will check the docs.....brb