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  • 720 Specifications


    Specifications:  AC Model 720 Tractor




    Power Lift System


    Onan, Model CCKB



    Hydraulic. 2.5 GPM (9.5 litres per minute) from the Hydrostatic Transmission charge pump.

    Type Gasoline, 4 cycle, twin opposed cylinders
    Cylinder Material Cast Iron   Relief Valve Pressure 550-700 PSI (3799-4828 kPa)

    Horsepower @ 3600 RPM

    19.5 (14.54kw)



    Hand Operated

    Bore and Stroke

    3.25” (82.5mm) X 3.00” (76.2mm)


    Hydraulic Cylinder

    2.5 inch (63.5mm) diameter - 4 inch (102mm) stroke


    49.8 cubic inches (816cc)


    3 Point Hitch (Optional)

    High Speed

    3850 RPM No Load; 3600 RPM Full Load


    Type Flexible Swinging draft hubs with ball couplers
    Idle Speed 1200 RPM   SAE & ASAE Category Meets Category 0 dimensions
    Valves Positive rotating Stellite facing on valve heads   Control Hydraulic, hand operated, same as power lift system
    Valve Tappet Clearance Intake .007" (0.152mm); Exhaust .016" (0.406mm)   Drawbar
    Valve Seats (Exhaust) Replaceable, Stellite faced   Type Single position - removable
    Cooling System Pressure air cooled, axial flow blower   Height 13 inches (0.33 m)
    Carburetor Zenith - Horizontal draft, adjustable main jet   Pin Size 3/4 inch (17mm)
    Choke Manually operated   Brakes Individual double disc type, can be locked together for simultaneous operation, parking brake is cam locking type.
    Air Cleaner Replaceable Dry Element   Electrical System
    Fuel Pump Diaphragm type   Battery 45 Ampere hour 12 volt, sealed terminals


    Cam gear driven, adjustable mechanical flyball, pressure lubricated

      Alternator 20 Ampere flywheel alternator with silicon diode rectifier
    Breaker Point Gap .020 inch (0.508mm)


    Regulator Transistorized temperature compensated voltage regulator
    Ignition Timing 20º before top dead center   Protection 20 ampere circuit breaker

    Spark Plug

    Champion H-8 or Allis Chalmers No. 2067308


    Lights Fender mounted sealed beams
    Spark Plug Gap .025 inch (0.635mm)   Dimensions

    Lubrication System

    Gear type oil pump, adjustable pressure relief valve, replaceable oil filter


    56 inches (1.4m)

    Length Overall 85 inches (2.2m)
    Starting Motor

    12 volt electric solenoid


    Width (overall)

    With Agricultural Tires (narrow setting) 43-1/4 inches (1.1m)
    Power Train



    With Agricultural Tires (wide setting) 48 inches (1.2m)
    Clutch Foot pedal operated, double V-belt drive, clutch by varying center distance between pulleys     With Turf Tires 50-1/2 inches (1.3m)<
    Universal Joints Disc type, self aligning, no moving parts              With High Flotation Tires 56-1/2 inches (1.4m)

    Hydrostatic Transmission

    Sunstrand - Variable delivery piston pump with fixed stroke piston type motor.  Replaceable oil filter.


    Ground Clearance (without drawbar)

    15 inches (0.38m)

    Gear Transmission 3-Speed Sliding Spur gear, Cast Iron transmission case, Rolling contact bearings   Turning Radius (with Agricultural Tires at Wide Setting)
    Differential 8 pinion, spur gear, non-adjustable limited slip.  Located in transmission case.     Outside Front Tire Inside Rear Tire
    Drop Housing Individual spur gears, rolling contact bearings, cast iron case.   Without using brake 8 feet 3 feet
    Using steering brake 6 feet 1 foot
    Steering Recirculating ball screw, manual operation.  3.2 turns stop to stop.


    Shipping Weight Approximately 1300 pounds (2860kg)


    Standard lever operated seat, adjustable from operator position. 4 inches (102mm) travel, front to rear.  Spring mounted, inclined ramp.


    Operating Weight (with 180 lb operator) Rear - 1000 pounds (2200kg)
    Front - 480 pounds 91058kg)
    Front PTO
    12 volt electric solenoid actuated clutch, with automatic brake.  Speed equal to engine RPM.


    Ground Speed Approximate, engine at 3600 RPM
    First Gear Range 0-4.2 MPH Forward, 0-2.6 MPH Reverse

    Rear PTO (Optional)


    Second Gear Range 0-6.3 MPH Forward, 0-4.0 MPH Reverse
    Third Gear Range 0=10.4 MPH Forward, 0-6.2 MPH Reverse

    12 volt electric solenoid actuated.  Rated at 100 ft-lbs (135 N.M.)


    Liquid Type and Capacity
    Fuel Tank 3.8 gallons

    Speed @ 3600 Engine RPM

    2000 RPM


    Engine Crankcase 3.5 quarts (above 32ºF, SAE 30; below 32ºF, SAE 5W-30)
    Drive Involute splined shaft   Transmission and Hydraulic System 6 quarts, Allis Chalmers Power Fluid 401 (Dextron)
    Direction of Rotation Clockwise (viewed from the rear)   Drop Housings, each 0.5 quarts, Allis Chalmers Gear Lube 715

    Source:  AC Operator's Manual, MODEL 720 Lawn & Garden Tractors, Part Number 1657026, November 1976.

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