Back burner has yellow flame

Make sure all the connections are tight. You could have something sucking in air as it heats up. If there is a loose fitting, propane can leak out, but as it flows, it can also suck in air.

Change the regulator

There is no air induction port (a la water heater) to adjust A/F percentage?

Ummmmmmm....

Second question

Stove manufacturers have no provision to adjust flame for sea level to 10,000 ft elevation?

Methinks something is missing here.

newman fulltimer wrote:
Change the regulator

That would be the regulator that is providing an output that burns with the proper appearance in the front burner and not in the back burner :?

I don't recall what brand my cooktop was but it started acting up in a similar manner. It appeared that the burners were getting too much fuel and there was no way to adjust the air mixture. My cooktop had a secondary regulator inside the stove. This is in addition to the tank regulator. I didn't care for the stove so I replaced it with a small residential cooktop.

It may be that the internal regulator went bad.

Take the entire burner off and soak it in a container of rubbing alcohol for a couple hours - the longer the better. Then get a bottle brush, or an aquarium filter tubes brush (there are many sizes) and go to town on the thing inside and outside, especially on all the little gas burner vents. Then soak it some more. Try to scrub it while holding it 'underwater'. This cured my yellow flame burner.

Alcohol is a great solvent and will loosen dirt, rust. etc so you can flush or scrub it away.

There is another possibility here. Since this is a used stove, perhaps a previous cook spilled salt water on that burner and there remains a little salt in/on it. Sodium will color a flame yellow, and if the salt were inside where it takes a couple minutes to get hot enough, that would explain that symptom. Neither mechanical cleaning nor alcohol would clear a salt deposit, but a goof water wash should do it.

pasusan wrote:

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The front burner flame gets more orange as time goes on too - but not as bad as the back burner.
...

That could be the main propane regulator at the tanks.
Although not sure why one is worse than the other.

Do the other propane appliances work OK?
Our furnace started sputtering and eventually stopped because of a faulty main regulator. The stove burners were tinged with yellow but worked.

OP here...

Thanks to all for the ideas and help. I ran the furnace with no problem and the stove burners are very very clean. I'm thinking it might just be the regulator in the stove top, but I'm going to hold off a bit on getting a new one since it's $45 for a maybe...

One regulator for all burners. Replacing it would be like replacing a compressor because one tire keeps going flat.