Sprint 375 Lawnmower?

Hi I am new to this site. I have a lawnmower with a 375 Sprint engine and lately it is running like it has some thing stuck in it, and its going through petrol very quick, when it is running to the last drops of petrol it stops sputtrer and seems to run okay until its dies because of lack of petrol. When I first check it was low in oil, so I topped it up. Can someone help please
Thanks