Hi everyone, my Petroflam has a hole on the mixing tube. Is this supposed to be there, or could it be a later modification? I’m having issues with combustion and I’m not sure whether I should block this hole or just replace the J-tube.
I think you can leave it there at the moment and see if you can make the lantern run perfectly as it is. I believe the through-holes had been added for some reasons. It might have been added to incorporate a mixing paddle to twirl, modify and improve the fuel-air mixing. Otherwise, as a trial, you can also temporarily block them off using some muffler cement or an aluminium foil wrap without introducing internal obstructions.
Strange fact since your petromax has the same "feature". It looks to be a 250cp model ? You can try it with holes but I have written more then enough why not. Also you should look at alignment. It looks like the gas jet is pointing sideways into the J-tube in stead of straight up. This too will effect performance. Cold spray test should be part of putting "humpty dumpty" together again.
