burner won't stay lit

[jfowells]

I have a gas water heater with an odd burner issue. The pilot stays lit, and in fact I'm able to light the pilot without pushing down the pop-up button, even when in the on position. It doesn't seem like the thermocoupler is requiring heat to maintain the pilot. Does this mean the pop-up is defective, and preventing gas from reaching the burner? When the pilot is lit and I turn up the thermostat, there is an immediate rush of gas to the burner, which fires up as it should, but just as quickly dies down to a flicker. The flame from the gas supply to the burner is big and yellow, but the burner itself seems to have a very limited gas supply. Barely a flicker from some of the ports (?), except in the back, where the flame seems stronger.

Does this sound like a thermocoupler/thermostat problem, or a block in the gas supply in the burner?

The thermostat is a Robert Shaw Unitrol, 68-184-335.
The heater itself is an American, installed in 2002.

thanks

[Gary Swart]

Folks like you that tinker with their gas appliances in spite of having no understanding of them scare the hell out of me. There are many things we can DIY, but there are some tasks best left to the trained and equipped serviceman. I don't mean to offend you, but do think about the consequences.

[Runs with bison]

It sounds pretty screwed up...to the point that it should be looked at by someone who can fully diagnose it. Most importantly, it doesn't sound like it is operating in a safe condition and needs professional attention: able to light the pilot when it shouldn't, operating with yellow flame (although this might just be due to start up condensation), operating with uneven burner pattern, and having it shut itself off quickly after ignition. With a 10 year old tank there could be any number of problems, so be ready for replacement.