Clog

Clogs occur when ash, dirt, dead insects or other debris become lodged in a pilot light's orifice, or the space where the flame should be burning. This causes the resulting flame -- if it ignites -- to be undersized and unsustainable. As HomeTips.com notes, you can clear out a clogged pilot light using a thin length of wire. First you should turn off the flow of gas to the appliance and switch off all the appliance's electrical components. You can then poke the wire into the pilot light orifice and push away any debris.

Low Flame Setting

A low flame setting is one of the easiest pilot light problems to repair. If your pilot light is unclogged but constantly goes out due to gusts from the wind, indoor fans or from people simply walking by and generating air movement, a low flame setting is likely to blame. In such a scenario, the gas flowing from a pilot light's valve is weak and incapable of producing a sustainable flame. To adjust the flame setting and increase the flow of gas to the pilot light, you will need to refer to an instruction manual. Some appliances have adjustment screws that you simply need to turn. According to HomeTips.com, the ideal setting will produce a pilot light flame that is between 1 1/2 and 2 inches tall. The flame should have no yellow in it.

Faulty Thermocouple

If you have cleaned out the pilot light orifice and adjusted the flame setting but the pilot light continues to go out, you may need to replace your gas appliance's thermocouple. Alternatively, you may just need to reinstall an existing thermocouple that has somehow become loose or dislodged. A thermocouple is a heat-measuring device that senses the heat of the pilot light and triggers gas to flow into the main burner of an appliance. According to The Family Handyman, some appliances have open burner chambers which make it easy for do-it-yourselfers to access and replace thermocouples. However, other appliances have closed chambers. Replacing the thermocouples of close-chambered appliances typically requires the help of a professional.