Hi, you would need to run it on a 1:40 mixture, which means, 1 liter of 2t oil for every 40 liters of petrol,or for every 10 liters of petrol, you`ll need 250ml of 2t oil. so about a bit less than half a liter per full 17 liter tank, but if you put the oil in, count on the volume of it.