The double mantled gas lamp post in front of our home is operational, but the light emitted is not very bright. The post is located about 40 feet from the main gas service at the meter, and the line serving it is 1/4" soft copper. Considering the length of the line and the amount of gas required, is this line too small? (The original owner/builder was an idiot) If I have to replace this light I would like to know if the line should also be replaced.
Replacing the lamp with an electric one is impractical due to problems with getting a electric line into the living space to connect to a switch.

Also, any advice as to how to troubleshoot the gas post would be appreciated!

Change the mantles? Do you have a valve to alow in more gas? If you like you could even go solar instead of electric but maybe their not bright enough either? You would have to check them out.

The mantles are new (and burnt in also) There also is a gas valve on the head assembly which can be opened and closed with a slotted screwdriver. As far as I know, unless something (an insect perhaps) has gotten into the orifices, the only thing causing the dimness could be low gas pressure because of the long run of small tubing.

The Pressure Is The Same All Over, The Volume Of Flow Is Another. A Two Inch Pipe Compared To A Half Inch Pipe Has The Same Pressure But Permits More Volume Of Flow Due To The Size Of Pipe. If You Know The Make We Can Research The Suggested Feed Size. I Believe That Slotted Adjustment Valve May Be For Air Mixing. And That May Help The Brightness, Not Sure. Maybe The Make And Model Are Working Properly And That All The Light You Get. Still My Choice Is Safe Solar Self Charging Units. What's The Make And Model I'll Look It Up

I will have to pry off the top of this puppy to find out what make it is. I would think that somewhere, there should be a minimun size requirement common to ALL gas lamp posts.

I will have to pry off the top of this puppy to find out what make it is. I would think that somewhere, there should be a minimun size requirement common to ALL gas lamp posts.

The rule of thumb is to run a 3/4" feed to the fixture, and then branch off from the gas cock with 1/2".

This covers both the BTU draw on the appliance, and also covers your butt if there are other high draw gas fired appliances or fixtures on the branch.

Really, though, in order to calculate the proper feed, I would need to know if you have low, medium or high pressure gas at the meter, what other fixtures or appliances are being fed from the trunk line, the size of the trunk line and the size and number of the branches.

I thought that 1/4" tubing was a little skimpy. Can I assume that the use of copper tubing outdoors is code legal in most states? (I live in PA).