It is in the limitations.
for CFM engines, starter time limitation is 2 minute (open).
Pause between start attempts, 20 sec.
Don't engage starter when N2 is above 20%
But an engine tailpipe fire is not an Emergency, is it?
So no hurry. Beacon light should be ON. The engine is built to have some fire in it. turn the Master OFF, call for the QRH procedure.