I've got an antique stove with an unusual problem. 4 burners light from one pilot. 3 of the 4 work normally. The last one will work if lit by a lighter directly.However, if will not light from the shared pilot. All orifices are clear of all grease, ash, debris, etc. Gas comes out of the ports on the side and goes down the pilot tube - but the flame does not chase it back down the tube to light the rest of the burner.Instead, there is just a constant flame coming out of the burner tube on the pilot side of the tube. (which means that gas must be successfully flowing out of the side ports of the burner down the tube, as designed.)The distances and clearances of the one that doesn't work is the same as those that do. The adjustable air vents are the same - though I also tried moving them from full close to full open and every point in between, with no change.I'm all of of ideas as to how to fix this.