I tried F34 which it the tube for 76/77 and this was undrivable. F9 tube used in DCOE32 for 1750 engine works the best for the moment. As it's already ordered, I shall try the F7 and if it's not better, I'll got back to F9, and try 140 and 145 jets.
Or I need to find a weber specialist with rolling road :-)
back to topic, my understanding is that with EmCon carbs you can not interchage E.Tubes like in the older ones, it doesnt work that way, like the tube has a lot more and bigger holes for the transition phase, older ones doesnt have this feature, stick with the original ones and play with the fuel and the air