An ERJ-170 Flight Crew experienced excessive ITT on a crossbleed start due to a sticky start/stop lever. They returned to the gate for a maintenance inspection and subsequently departed.

Narrative

On an attempted crossbleed start; we exceeded the engine ITT start limitation by 10 degrees for 1 second. We were taxiing out on one engine with the APU off. After coming to a complete stop; we initiated a crossbleed start of engine 2 after the pressure on engine 1 was brought up to 44 psi. Both the Captain and myself were monitoring all engine parameters. We noticed that the engine 2 ITT was slowly rising into the 700 range. The engine maintained a steady temperature of 715 for a few seconds and then it began to rise at a very quick rate. As soon as this rise started; a shutdown of the engine was initiated. However; the engine 2 start/stop switch seemed to be sticking and would not allow an immediate selection to STOP. I had to use two hands to bring the switch to the stop position. By the time I was able to do this; the engine had exceeded the 815 ITT start limitation by 10 degrees for one second. An engine exceed EICAS message was displayed and we returned to the gate. Maintenance was called. A visual inspection of the engine was done and an engine 2 start at the gate was performed to monitor its parameters. All parameters were normal. Maintenance cleared the EICAS message and the flight proceeded to ZZZ without further incident.