The brakes on this machine are powered by the hydraulic system (CHIP Brakes) after the flow divider to the power steering. Make sure the fuel mixtures and timing are correct. There is a vacuum diaphram that boost the throttle when the engine vacuum drops due to engine loading. To test it the engine should not stall when the steering is deadheaded. If the operator of this machine wishes to operate the steering when the machine is stopped he should use the inching peddle to stop then release the pedded enough to reduce engine load that is appling the brakes then operate the steering.