You say you have a 14" McCulloch that leaks oil, tell us the exact model of the saw because there are a lot of them.
One thing to consider is that every chain saw made has an air inlet hole in the oiler system to let air back into the oil tank as the oil is pumped out. On some saws this inlet may be slightly below the highest level of the tank and if a saw is stored with the oil tank completely filled then normal temperature changes cause expansion of the oil and push it out the vent hole. Usually it will not cause the whole tank to empty though. One some other saws that use a pressurized oil tank system you have to bleed the pressure from the tank when you have been cutting before you store the saw, otherwise the pressure in the tank will force all the oil out.
