I have the Ts and Cs. Here's my take on underburning . The radiant heat of the brass burner is causing the fuel to underburn. I believe it happens because of the wide range of conditions the stove can run in. . If you turn it down from a high setting and it doesnt cool fast enough for the smaller flame. The lower pressure allows the flame to suck under the burner. Also wind will allow it to happen too. Generally i dont use the windshield if its hot . To disipate more heat out. And I shut off and relight it from the top. Ive got Ts with no holes and with holes in the center tube. And a C without holes too. I see it like this. The stove runs in 100 below zero and 130 F. And any fuel you can put in it and a very adjustable flame. To do this requires a balance of heat disapation over a wide range which allows underburning to happen when its too hot and the flame is too low. or you blow it out , or the wind does. To stop underburning, you would have to make the stove burn less over a wide area of temperature difference. Or with less flame adjustment. Probably at the lower temperature end. By making heat disapate fast enough to prevent it, it would cause it not to run in cold weather. By making the stove run in really cold weather. it makes it underburn when its too hot or the flames too low .
I have found that underburning may be caused by heat distortion of the outer cap - where it mates with the burner skirt.Try circular grinding it lightly on a flat fine oilstone,only untill it has a continuous shine on it's entire circumference.Also check that the jet itself is secured properly,so it doesn't leak from its thread.Hope this helps.
