gas cooker?

I have a new Cannon C60gpx cooker and the main oven sparker stayes on even when lit for 10 mins... I have installed the LPG conversion kit, the kit was missing the size 71 injector so I used the 72 one I had replaced from one of the rings, would this make a difference? also The Propane gas bottle is getting a bit low, could the problem be pressure related? all the other burners use manual igniting(via push and "spark" knobs), but the main ovens is automatic.