Scott Bonnar 520 & 720 Series Rotary Mowers — Operating Instructions

Operating instructions for the Scott Bonnar 520 and 720 Series rotary mowers — starting, fitting and removing the grasscatcher and safety flap, folding the handle, adjusting cutting height, air cleaner servicing and fitting new blades, with the replacement blade set part numbers.

• Models520 and 720 Series rotary mowers
• Pages4
• Publication1942876

Download the original PDF (1.1 MB)

Skip to the full text ↓

Read it here

Every page of the original is reproduced below — no download needed.

Full text of this manual

A full transcription of Scott Bonnar publication 1942876, the operating instructions for the 520 and 720 Series rotary mowers.

Before starting

Read the separate engine operating instruction sheet before starting the engine.

Caution — the engine does not contain oil when purchased.

1. Fill the crankcase to overflowing, with the recommended grade of oil (Castrol GTX).
2. Fill fuel tank — use standard grade petrol (do not mix oil with petrol).
   Note: initial starting will be easier if the tank is completely full.
3. To start — move the throttle control lever into “Fast” position. (5 h.p. model only — place in “Start” position.)
4. Place foot on mower as illustrated to prevent mower from lifting, and grasp the mower handle with the left hand. Ensure that the left foot is well clear of the mower. Pull the starter cord with a long smooth action without jerking.
5. Always start the mower on clear level ground, not in thick grass or hazardous areas such as gravel paths.

Mowing with catcher

For maximum safety your mower is fitted with a Safety Flap that automatically drops and closes off the grass chute when the grasscatcher is removed. Unless the flap is correctly retained in the fully raised position when the grasscatcher is fitted, the mower will not catch grass.

To attach

1. Raise the safety flap (A) as high as possible by pressing down on the flap lever (B).
2. Retain the flap in this position and move the catcher into position with the flap entering into the catcher opening.
3. Make sure that the top inside surface of the catcher slides along the rear edge of the raised flap, so that the edge of the flap will slide into the retaining clip inside the catcher.
4. As the catcher is slid into position, hook it onto the upstanding lugs on top of the mower chute.

When correctly retained in the “catching” position the lever (B) is in a level position and cannot be moved.

To detach

1. Press down on lever (B) until the catcher is removed.
2. Lift off catcher and move it backwards from mower.

Note: the catcher can be attached and removed in one action, by keeping the arm below the handles, instead of having to change the grip.

Mowing without catcher

The “Safety Deflector” illustrated is an accessory that can be purchased from your dealer.

If long grass is to be cut a deflector must be used for complete dispersal of the grass and to prevent clogging of the chute. Before fitting the attachment stop the engine.

To attach — raise the safety flap (A) by pressing down the flap lever (B) and hook the tongue on the deflector over the flap pivot bar. Lower the flap so that the retention lugs (D) enter the slots in the safety flap. The deflector will now remain in position.

To disengage the deflector, lift safety flap.

Folding handle

The handle can be folded back for mowing under branches and shrubs or forward for convenient storage.

To fix handle in mowing position, raise handle until it is correctly aligned with the lower handle (A). To fix in position, move the locking cam lever (B) towards the upper handle bar (C).

Should the handles not clamp tightly enough, additional clamping effort can be obtained by slightly tightening the adjusting nut on the other end of the handle pivot.

Adjusting handle height

Lock the handle in mowing position. Loosen the handle holding nuts on both sides of the mower. The handle can then be raised or lowered by a pivotting action — re-tighten nuts.

To adjust height of cut

The cutting height control lever provides adjustment on all four wheels at once. The cutting height is raised by moving the handle forward. To disengage the adjustment lever from the engageing slot, apply slight outward pressure on the lever. Upon selection of the desired cutting height, the adjuster locks into place on release of the handle.

Maintenance

Air cleaner (mounted on handle)

1. Before servicing, pull the plastic breather tube off from the air cleaner housing — this will prevent dirt from entering the engine.
2. Unscrew the cap and remove the filter element. Tap the element on a hard surface to dislodge dirt and grass particles.
3. Remove any debris from inside the housing.
4. On re-assembly make sure that the open end of the filter is downward. The filter must not be washed in petrol.
5. Replace the breather tube.

Note: for engines fitted with engine mounted air cleaner — refer to engine sheet for maintenance instruction.

Mower base and grasscatcher

For efficient performance and grasscatching, the underside of the mower, the grass chute, the safety flap and the air screen in the grasscatcher must be kept clear of grass and dirt build up. Hose clean after use — do not direct water onto the engine.

Wheels

Wheel bearings are greased on assembly. It is advisable however, to occasionally prise off the hub caps and apply a little oil to the axles.

General

Occasionally check all nuts and bolts for tightness. For detailed engine service refer to the engine maintenance instruction sheet.

Fitting new blades

The mower should not be tilted sideways as oil may enter the engine cylinder.

1. Remove spark plug lead.
2. Remove petrol cap and drain fuel to prevent spillage.
3. Fold the handle and tilt the mower backwards.
4. The mower should be positioned on a support high enough to allow access to the blade nuts, through the discharge chute opening.
5. Remove blade. It is advisable to replace the blade bolt and blade bolt nut after 3–4 blade replacements, or sooner if the bolt head is damaged.
6. To attach new blade:
   1. Insert blade bolt (1) from underside of rotor.
   2. Place blade (2) on bolt.
   3. Place D-washer (3) on bolt.
   4. Place tension washer (4) on bolt with concave side facing the blade.
   5. Place plain washer (5) on bolt.
   6. Fit locking nut (6) and tighten securely.

Always replace both blades as replacement of one blade only will result in the machine being unbalanced, which will cause excessive vibration.

Part numbers for replacement blade sets

• Blade Set — 5001328
• Blade & Bolt Kit — 5001344

For optimum performance replace with genuine Scott Bonnar spares.

Warranty (as printed)

Scott Bonnar Limited undertakes to repair or replace without charge to the original purchaser any part of the mower which shall fail within a period of twelve months from the date of purchase where in the opinion of Scott Bonnar Limited such failure is due to defect in material or workmanship embodied in the mower.

Where the mower is used for other than domestic purposes, the warranty shall continue for a period of three months only.

The obligations of Scott Bonnar Limited shall extend only to repairing or replacing such part at its service branches or at the premises of an authorised service representative.

Conditions

• All transportation charges on, and damages and loss incurred in connection with the transportation of mowers or parts submitted for repair under this warranty shall be borne by the purchaser.
• This warranty does not apply to defects which, in the opinion of Scott Bonnar Limited, are caused by accident, wear or tear, misuse or neglect, or by interference with the construction of the machine as completed by the manufacturers.
• Items such as cleaning of spark plugs and carburettor jets, adjustment of cutters etc., are not covered under this warranty. While the services of our representatives are available to carry out minor adjustments, a charge is made to cover travelling and time involved.
• Warranty in respect of the engine is as laid down by the engine manufacturer.

Due to our constant efforts to improve the performance and design of our product, slight variations from the illustrations may occur.

This warranty is reproduced for historical completeness only. It expired with the original purchaser decades ago and confers no rights today.

Scott Bonnar service centres (as printed)

Head Office: Scott Bonnar Limited (member: Challenge Corporation Ltd.), registered office and factory 33–47 Holland Street, Thebarton, Adelaide, South Australia 5031 · Telephone 43 9155.

Scott Bonnar Sales Pty. Ltd. service centres:

• South Australia: 33–47 Holland Street, Thebarton 5031 · Telephone 43 9155
• Queensland: 27 Ipswich Road, Woolloongabba 4102 · Telephone 391 2676
• Western Australia: 104 Belgravia Street, Belmont 6104 · Telephone 65 1288
• New South Wales: Clyde Industrial Park, 321–325 Parramatta Road, Auburn 2144 · Telephone 648 0431
• Tasmania: Mr. David Tonks, c/o Scott Bonnar Limited, P.O. Box 98, Moonah 7009 · Telephone Hobart 72 5477
• Victoria: 265 Huntingdale Road, Huntingdale 3166 · Telephone 544 1277

Transcribed from Scott Bonnar publication 1942876. The scanned pages in the viewer above are the authoritative source. The back page of this copy carries the original owner’s handwritten note — “Model 520, No. 28065”.