Cub Cadet 72 funny starting.

A friend of mine recently bought a cub cadet model 72. It runs good and seems real powerful, but its funny when it starts.
When you first hit the key nothing happens, then you figure "oh man, dead battery." But if you then hit the key again it'll crank. Slow at first but it'll build up steam. If you let off the key and go back on you keep the speed you had before, its like just cranking makes it crank better.
So then it'll start to fire, once, twice, a couple more times, and then start and run good.
I think the hardstart is due to needing a tuneup, but the starter's got me cornfused. Should we take it (the starter) to a shop and have it looked at? Is this a common problem?