Abstract: A control system for regulating starting and various operations of a walk behind and self-propelled trencher. The control system conditions the trencher for forward, neutral, and reverse operation through use of a single control lever mounted for sliding movement in a common plane extending between a neutral/start position and a drive position and thence in another plane to forward or reverse positions to control the direction of the trencher. When the control lever is in a neutral/start position, a power assembly on the trencher is ineffective to drive wheels used to propel the trencher across a field. When the control lever is shifted to a drive position, a drive path is established between the power assembly and at least one of the wheels on the trencher. The control system is configured to allow the power assembly to be started only when the control lever is in a neutral/start position and prevents starting of the power assembly when the control lever is in other than a neutral/start position.