The Ignitor? would not spark to light the burner.

First I unplugged the electric line to the range. Then I removed the screw that holds the burner in place and then lifted the burner up. Pulled the elec line off it and then took the ignitor/sparker? out of the burner. inserted the new one and put the elec wire to it. screwed it back in place and turned on elec and tried the burner. But now it sparks sometimes and sometimes not. And only if holding the gas on longer than I want as it stinks up the kitchen and is dangerous. What else does this burner need to work properly?