Ken Theis

Brand new DRT900H tiller. Put it together runs great on idle or moving it to the Garden. I can engage the tines in the air and still runs good. As soon as I drop it in the groud,under load the engine surges constantly and consistantly. No change in the RPMs as it hits harder or softer soil. The machine bounces forward and back. This can't be normal? Somewhat hard to handle when tilling. Locale dealer is working on it and can't seem to figure it out. Replaced Carborator, he feels that it is not normal but is it a characteristic of the tines or this machine? Anybody have the same problem?