No it's not normal for any tractor to use this much oil, unless of course its old and worn out, does the ym1700 have a difficult time starting? How many hours showing on the meter? is this a reconditioned unit?
X2 on what Winston1 stated, the most I have ever had to add is about 1/2 quart toward the end of the season, in fact about now it would likely need some oil,