Question about 2 stroke scooter oil tank.

[willmon22]

I have a 2005 Vento Triton r5 2 stroke scooter and I was wanting to know how I would know that the oil tank is actually working and mixing the oil with the gas. The person I got it from runs a scooter store and fixes them and everything and told me that he is not sure if it is working or not. So he told me that I need to put some oil mixed in the gas just to make sure. So I have been doing that and it seems like I am getting very terrible gas mileage. It is like I go about 20 miles maybe and it has about a quarter of a tank left. And I think that is terrible as my 4 stroke can go at least 70-100 miles and the tank is finally almost empty. So is it this way because of mixing a little gas in the oil tank and putting 50:1 oil mix in the gas tank? If this is the case I would like to be able to know for sure that the oil tank is working before I put straight gas in the tank and straight oil in the oil tank. As I am sure the scooter probably wouldn't run very long if it isn't getting little to any oil come out of its tank.