Remove of the burner orifice caps, and take it to a local gas appliance repair shop for a match for as many caps as you need sized for natural gas use. If you have trouble finding them, you can always solder the holes in your present caps and redrill them to one half the diameter they are now. You'll also need to replace the gas presssure regulator with one rated for natural gas use.
When the correct parts are installed, adjust the burner air shutters for a bright blue flame with minimum yellow tipping.
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Maybe I was unclear. The cooktop, in its native state, is set up for natural gas and I wish to convert it for LP operation.
Where are these burner orifice caps? Are they attached to the individual burners or part of the plumbing coming from the valve?
I can see that soldering to fill, then redrilling smaller would go in the right direction by restricting the pressure arriving at the burner. That's good.
But as to the regulator, you've got that dead wrong. I'll need a regulator rated for LP to meet my goals.
Let me know what you think and where I'll find these caps.
My apology. I lost track on the regulator, when I said to install a natural gas unit. Of course you should install a pressure regulator that's rated for propane use. The orifice caps are the jets that fit into the throat of the burner assemblies, through the air adjustment shutters.
Generic orifice caps are available with a predrilled #72 hole, which can be sized up as needed. Most gas appliance technicians stock them. The reason you need to match your original caps is that they come in many sizes, shapes and threat sizes.