Finally, troubleshooted the engine turn-off problem.

There was an voltage drop or cut-off to spark the engine due to sub-standard coil which I dint replace during my rebuild.

Also the CDI unit was very weak so that I had to fix both of them to resolve the issue.

Odo is now 1000 approx. having a crispy ride all the day.

Credits to Mr.Boss - For giving me a head'sup to check on the ignition coil.