Customer had problem with new hydraulic cart, which appeared to be locked up. In nine times out of ten, this is a hydraulic lock caused by dead heading the system. Most portable carts have a flow control valve and setting this to off will return pump flow back to tank. If the valve is damaged, connect the pressure hose to the return (tank) hose to relieve pressure. If this case, the cart must have been knocked over for some time which allowed crankcase oil to fill the engine's combustion chamber. Although not a huge problem. the spark plug needs to be removed and the engine turned over several times with the ignition turned off. A rinse of gasoline or carburetor cleaner helps break down the residue before reinstalling the spark plug.