Power lift

A method of controlling a power machine having a frame, a boom pivotally coupled to the frame, a lift cylinder coupled between the frame and the boom to raise and lower the boom, a slave cylinder coupled between the frame and the boom to aid the lift cylinder in raising the boom, an implement interface which an implement can be mounted, a tilt cylinder coupled between the boom and the implement interface to control rotation of the implement interface and implement relative to the boom, a power source configured to provide pressurized hydraulic fluid, and a control system configured to control provision of the pressurized hydraulic fluid from the power source to the lift cylinder, the slave cylinder and the tilt cylinder, the control system including a lift control valve coupling the power source to the lift cylinder and having a non-actuated position and first and second actuated positions for extending and retracting the lift cylinder, a tilt control valve having a non-actuated position and first and second actuated positions for extending and retracting the tilt cylinder, the method characterized by steps comprising:

• actuating the lift control valve to the first actuated position to provide pressurized hydraulic fluid through the lift control valve to the lift cylinder to extend the lift cylinder and raise the boom;
• identifying a condition of the tilt control valve being in the non-actuated position while the pressurized hydraulic fluid is provided to the lift cylinder and responsively providing pressurized hydraulic fluid through the lift control valve to the slave cylinder to extend the slave cylinder to aid the lift cylinder in raising the boom;
• and
• identifying an increase in pressure in the slave cylinder and responsively causing increases in pressure in the tilt cylinder, resulting from a load carried by the implement, to be communicated to the slave cylinder to further aid the lift cylinder in raising the boom.