King kooker will not burn a blue flame, only a big yellow sooty

Tank could be too cold to make vapour . Try a wine making heat pad under the tank .

clean burner tubes

clean burn gas is a blue flame
it is achieved by using the correct jet size for the gas in use and by adjusting the air shroud around the jet opening
if you converted from natural gas to LPG and didn't change the jet size that is one reason
next there is a tin type shroud around the jet area that can be moved back or forward over the big hole that lets air to mix with the gas at the jet
the position of that shroud adjusts the air to gas ratio
If you are not sure of what I am talking about , talk with a gas fitter or have them do the job

Ream out all the orifices and air venturi holes on the burner, adjust the air-ahutter, the air-shutter is usually nearer the valve/knob than to the burner. Yellow flame is an imbalance of fuel to oxygen and is creating Carbon Monoxide and not burning cleanly... this is the same problem that can make a furnace deadly. Blue flame=neutral flame.

Are you smelling gas around the grill or tank? Fill a spray bottle with soapy water, slowly turn on the tank valve, and check for leaks at the tank valve, hose, regulator, as well as each gas valve (remove the knobs first). If no smell or leak is found, check your burners to see if they are burning mostly blue. If they are lazy yellow, they could be dirty or partially clogged and require cleaning; or possibly rusted through and need replaced.. If you do have blue flames, consider turning down the burners for a reduced flame and see if that helps.

First, is your grill on a cart or built in to an island? Secondly, are you using a 20lb propane tank to fire the grill or is it hard piped to the grill from your house? And finally, has it been converted from Propane to Natural Gas?

If you're using a 20lb LP Grill Tank are you sure there's still gas in the tank? Did you just installed a new, full tank recently and the problem started after that?

If the latter is the case, turn off the grill tank valve and disconnect the hose from the tank. Wait 5 minutes and reconnect the hose to the tank. Turn the tank valve ON VERY, VERY SLOWLY, until it's fully open. Light each burner one at a time and turn then to high flame. Do the flames look normal? Are they the proper height? Is so, you just solved your problem. Remember to turn the tank valve on very, very slowly after turning it off each time.

If you grill is hard piped from your house, be sure that the gas line shutoff valve is turned ON.

Hope this helps solve your problem.

Check your propane tank first; is it getting close to being empty? Check where the hose connects to the burner, there should be an air adjustment there; it looks like a rotating disc with two big holes on either side, this is turned when the burner is lit to adjust the amount of air mixing with the gas. If it's all the way open, you have a yellow flame, if it's closed all the way you have a blue (but weak) flame. Try adjusting that and if that doesn't work, try a different regulator...it is rare a regulator could cause this but it could cause it; just use that as your last resort.

natural gas nozzles are sized diffrent than lp gas.not safe to convert.should consult manufacturer

leave the propane tank on and install a gas ball valve after the tank. you can see that the gas is on by the position of the valve,

A clue to what could be wrong is that you mentioned it took 10 minutes for the pilot to go out. It could be your gas valve. Get a technician in to check your gas pressure both before the gas valve and after. Have them check it as the water heater is running.