BarbreJ you should only have to hold the button down till the sensor gets hot enough to keep the gas flowing. There is a tab with a whole in it that puts the tip of the sensor right at the edge of the burner, the sensor should have two nuts on it so you can lock it down. If you need me to I can post picks for you.
* (Swinging club) Whack! whack! whack! *
Nope, the old nag's still dead .