Tillers

I just purchased a new DRT900E tiller. I used it for the first time and after about a half hour of use the engine quit. I thought maybe there was too much grass in the tines so I clean those. I was able to restart it, but it ran for less than a minute, stalling again. It was full of gas and I checked the oil at the lower oil opening and it was near the top. I was tilling in soil that had been tilled last year so it wasn't working really hard. I just started it and now it will run. The problem is it runs best one notch below full choke. If I go all the way to run it stalls. Should I just take it to a service center for warranty work? Any help would be appreciated.