Not light my pilot light is lite but the heater wont start heating

Check to make sure that the poilet lite flame is touching the tip or top of the thermocouple.
the pilot lite needs to heat up the thermocouple so that the thermocouple opens the gas to the main gas log. a cold thermocouple shuts off the gas to the main gas log or gas burner and a hot thermocouple opens the gas to the main burner.
the pilot lite flame must be touching the thermocouple to heat it up.
pilot lite orface needs to be clear to let the pilot flame gas through with enough pressure so that the little flame can reach & touch the thermocouple. Pilot lite gas feed tube must be clear to let gas through. Use compressed air or a fine sewing needle, or even carb cleaner to clear out orface hole and gas feed line to pilot lite.

important!! WARNING:
if you use carb cleaner,make sure all the carb cleaner is dry,soaked up with paper towell or kleanex tissue and blowed out with compressed air , because carb cleaner can burn just like gasoline; so any carb cleaner must be compleatly gone before you attempt to lite the pilot lite.