General Mower Requirements
All who wish to enjoy the mower sport must adhere to the following requirements listed below.
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****NOTICE****
These general requirements apply to ALL racing classes.

  1. Cutting blades must be removed completely from all mowers. All mowers must have a cutting deck securely mounted in the stock position, with a minimum of 2.5" ground clearance under the lowest point of the deck.

    3. No overhead cam engines or liquid cooled engines in any class.

  3. All non-stock mowers MUST be equipped with an automatic throttle closing device.

  4. All mowers MUST be equipped with a kill switch, which will turn off the ignition if the driver leaves the mower.  Mowers shall use a tether, mechanically attached to mower and driver. Velcro is not acceptable. Pressure switches are not allowed. Kill switch must remain in closed position (engine not running) until
    driver mounts mower. Additional switches that can by-pass the kill switch are not allowed under any circumstance.
     A. The ignition interrupter kill switch and cap/prong must be commercially available for racing type
         vehicles such as jet skis, snowmobiles, 4-wheelers etc. Magnetic or any other form of homemade
         switch is not allowed.

  5. Mower brakes must be in good condition, easily operated and operating on at least two wheels.
  6. Brakes may be improved in any way.
  7. Throttle and brake controls may be relocated.
  8. FRAME: Discrete strengthening is allowed. Front and rear axles must use original frame as primary mounting point.
  9. Mowers must be free of projections, which could injure the driver or a competitor, or damage another mower. No axle or wheel mounting bolts may protrude beyond the face of the tire sidewall.
  10.  Mowers must be safe and complete, all parts and panels in place, with no missing nuts, bolts, cotter keys, etc.
  11. All exposed chains and sprockets must be fitted with metal guards, which will direct a broken chain downward.
  12. Mowers must be neat and clean, with paint in new or very good condition. No excess dirt, oil, grease, rust or primer. Sponsor graphics must not interfere with mower’s racing numbers or class letters.
  13. No bumpers, nerf bars or push bars.
  14. All mowers that do not have the top of the engine completely covered by the hood must have the flywheel covered by either the recoil housing, the stock wire housing or racer made cover.
  15. Race numbers should be a minimum of 5” high and of a sharply contrasting color from their background, and should be visible from all four sides of the mower. All mowers must have their number visible from the front for grid line up and scoring purposes. It is recommended that racing numbers be pre-registered with the RACE NUMBER COORDINATOR. Machines without numbers will have them assigned on race day. Racing numbers are “owned”, and will force unregistered duplicates to change. Class letters, should be a minimum of 3” high, and be shown on both sides of the mower.
  16. All positively charged terminals must be insulated with a cover or heavy tape, and battery must be well secured.
  17. No offset or stagger. Body must be mounted in the center of the wheels. Tires must match in size per axle. Lawn mower seats only, in the stock location, no lower than the tops of the fenders or exposed rear tires and on centerline. Offset measured from centerline to the outside of tire sidewall. Wheelbase may not be altered.
  18. Glass headlights must be taped or removed.
  19. Maximum width 38” sidewall to sidewall unless otherwise stated in the class build section
    20. .
  20. Steering wheels and handlebars may be replaced with any commercially available pieces, but not substituted for each other. May not be mounted off center unless originally mounted offset. Steering columns must pass through the original hole in hood or dash at the original angle.
      A. Handlebar type grips may not be added to steering wheels.
  21. Tires must be lawn tractor tires. No Snow Hog, tiller, A.T.V, or performance compound or competition kart tires. Flat tires will be black-flagged!
  22. No centrifugal and/or torque converter clutches.
    24. Minimum 4” ground clearance to frame, 2” ground to deck.
  24. All mowers must utilize a clutch.
  25. Flywheels
     A. Unmodified Stock.
     B. 100% Billet.
    C. Modified Stock along with an approved scatter shield (guidelines below).  

****NOTICE****
 All Scatter shields used on USLMRA lawnmowers must adhered to the following specifications

  • Scatter shields must be fabricated from 1/8" steel minimum.

  • The scatter shield must be form fitting and follow all of the contours of the blower housing.

  • The scatter shield must be the same height (vertical shaft) or same width (horizontal shaft) as the blower housing and be bolted to the block using the original mounting points.

  • A 1" X 1/8" minimum steel strap must run across the face of the blower housing to reinforce the scatter shield, side to side.

  • Notches for starter drives must be reinforced to at least one inch past each end of the notch.

  • Any holes drilled into shield for items such as dip stick holder or fuel pump must be 1/4 inch or less.

  •  The scatter shield must be painted to match the engine’s blower housing.

26. Fuel and Fuel Delivery: Fuel lines must be clamped at all joints. Electric fuel pumps are not allowed.

 

Racing Classifications

Class designation STOCK-S/P,  and MODIFIED-B/P.

     ***************WARNING***************
     Remove mower blades before modifying or removing the engine governor.
Governor alterations will allow the engine to over speed, which may
     cause blade or blade assembly to explode, presenting grave danger to
  participants, spectators and officials around the mower and may lead
     to damage of the engine and/or engine components.
     ***************WARNING***************

****NOTICE****
 These mowers are delivered from the factory except for the modifications listed below.

  1. Engine must be originally manufactured for use in lawn mowing equipment and be stock in appearance, with the exception of air filter, air cleaner or velocity stack. Crankshaft must be in original orientation and clearance hole in the frame. Engine may be internally modified.
  2. Exhaust design is open, but must terminate away from driver and competitors,
    in a rearward and/or downward direction and present no apparent safety hazard.
  3. Starter must be onboard, either electric or pull-rope.
  4. Driveline may be modified from the engine pulley to the rear wheels, but must
    utilize a shift able lawnmower transmission or transaxle, No Vari-drivers, Hydro
    or Hydrostatic units may be used.
  5. Rear axle must use a locked or solid axle. No single wheel drive.
  6. No centrifugal and or torque converter clutches.
  7. Rear axle must use shaft locks, center bolts, or thru-bolts to secure the rear
    wheels.
  8. All steering linkages must use ball-type or spherical threaded rod ends.
  9. Front axle may be pinned, bolted or welded into stock position. No suspension,
    no shock absorbers. Axles must have a 1-piece beam.
  10. Front axle and steering may be reinforced, substituted or fabricated. In the case of racer-fabricated axles, these will be subject to the judgment of the Technical Inspector as to their apparent safety for racing. Aluminum may not be used as the material for the one-piece axle.
  11. Shaft locks, center-drilled axle with locking bolts, castellated nuts with cotter
    pins, are acceptable for securing front wheels. Cotter pins, E-rings and C-rings
    alone, bent nails, hitch pins, over-center pins and quick-release pins are not
    sufficient for wheel retention and are not approved.
  12. Wheels must be the same size on each axle, of any origin, made of metal. No dual or tandem wheels.
  13. DECK: Mowers must mount steel factory decks: The deck must be at least as
    wide as either running boards or body edge whichever is wider. Decks may not
    extend any more than 2” beyond the tire sidewalls on each side. Deck halves
    may be mounted to running boards. Decks must be secure.
  14. SAE-rated trailer or lawnmower tires must be used.
  15. Footholds must be discrete, and no more than 2” high, made of flat or “L” stock (no rod stock), and made such that the foot can not become entangled in a rollover.
  16. Class is determined by the OEM factory rating of the lawn mower engine.
  17. All parts should be of lawn mower origin with the exception of those specifically mentioned above or otherwise allowed under Sec. VII.
  18. Hoods and body parts such as fenders may be upgraded from year to year only if the parts are from the mother company and any subsidiary company of said mother company.
  19. External ignition Systems are allowed.
  20. Aluminum Flywheels are allowed.
  21. Fenders may be discreetly moved but not altered.
  22. Must use axle mounted brakes, no lawnmower transaxle or transmission mounted brakes.

Engine Class Defined

Based on OEM BLOCK designation
 .
S/P: STOCK
Valve-in block single cylinder 4 stroke engines over 8.5hp All single-cylinder
overhead valve and two cylinder valve in block, 4 stroke engines, 20hp and under.
 39”~42"minimum unaltered wheelbase. Mid engine frames are not allowed. 5”
minimum front wheels. 8” minimum rear wheels.
 
B/P: MODIFIED
(INTENT: To allow competitors the opportunity to compete in a faster class of racing. Mowers must maintain a recognizable form of a lawn mower.)
All overhead valve V-twin 4 stroke engines, 20hp and under. 42” minimum unaltered wheelbase. Mid engine frames are not allowed. 6” minimum front wheels. 8” minimum rear wheels.