13 GPM 2 Stage Pump / Coupler / Pump Bracket. Components for use with AW(ISO)-32 (10w) or AW(ISO)-46 (20w) hydraulic fluid. Do not use "tractor transmission fluid". Pumps work in horizontal and vertical positions. Displacement High Pressure: 0.219 cubic inches/rev. Displacement Low Pressure: 0.537 cubic inches/rev. Unloading Valve Preset Pressure (psi): 600 to 700. Hole pattern for motor is drilled to fit on a variety of engines. Most common to find this spacing on a Honda GX series motor between 8hp and 13hp, as well as Loncin and Lifan motors between 8 and 15hp. Bolt circle: 3.5 ...