Repaired 111T Burn Testing 

Well, that would really depend on what stove you have, what it's condition is and a whole lot more besides. RU-vid comments is not really the place to be working this sort of stuff out. For help with your stove, send along some pictures of your stove and a description of the problem to my business email at: berniedawgstove@comcast.net Thanks! BD

Yes, preheat is required on the Optimus 111T stove and many others, including (in a different fashion) your Coleman, too. But, not because the 111T stove has a pump - pump has nothing to do with it. Preheat is required to heat the burner hot enough to vaporize the fuel on this type of stove. Your Coleman is not the same stove. Your Coleman is a different stove than this Optimus 111. Your Coleman has a generator. But, it, too, needs its generator preheat to burn fuel properly. Your Coleman has a built-in feature to limit the amount of air on startup and allow the mist of fuel and air to burn to preheat the generator on startup. That's why there is a little lever you move on your Coleman (most Colemans anyway) when you are starting up. BD

@@BernieDawgCinema Yes, ... I can say "simplified preheating"

@Jacek Czerwinski Yup. That describes it. Very clever guys at Coleman. Safer stoves, too. 👍 BD

Thank you!