Uflex Mercury 75-115hp Zero Torque Feedback TillerMercury 75 115hp Zero Torque Feedback Tiller Todays four stroke outboard engines are generating high torque loads which can make tiller steered boats difficult to steer. The Uflex ZTF Tiller systems eliminate propeller torque at the tiller handle when the driver is not actively changing direction. Using a patented hydraulic valve, the propeller torque is locked from reaching the tiller handle unless the driver pushes or pulls on the end of the handle,