I think it important that you find out where it's leaking from. Adding oil every time may be your problem. You only add oil when it's low. Adding more will cause it to push oil out the filler/breather cap. Clean up the deck well, run it for a while and see where it's coming from. If it's coming out of the filler/breather cap, you need to reduce the amount of oil. Usually you have a filler on top and a level port on the side somewhere. When filling, you open the level port and fill until it runs out at that level. Any more and it's too much. Usually use 90W gear oil, but follow your owner's manual instruction. John