The factory operating and maintenance instructions for the Scott Bonnar Model 45 petrol reel mower — how to set the cutter, tension the chains, adjust the deflector, clutch cable and handles, and where to oil it. Covers the 14-inch, 17-inch and 20-inch models, with nine reference photographs.
- Models450415 (14″), 450423 (17″) and 450431 (20″)
- Pages3
- Publication1941452 · 8/68
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Full text of this manual
A full transcription of Scott Bonnar folder 1941452 (dated 8/68), the operating and maintenance instructions issued with the Model 45 Series petrol reel-type mower: 450415 (14″), 450423 (17″) and 450431 (20″).
It takes only a few minutes to read this folder. The helpful tips which it contains are important to the continued operating efficiency of this machine.
The lettered references (A, B, C…) and figure numbers below refer to the nine photographs on the inside spread, which you can see in the viewer above.
Starting and operating instructions
To start and stop. The method of starting and stopping is described in the Engine Instruction leaflet.
Caution. Do not fill the fuel tank while the engine is running. Avoid spilling fuel on a hot engine — this may cause an explosion and serious injury.
To propel the mower. Engage cutter by turning engine clutch lever (A Fig. 1) upwards. Then gently squeeze the clutch (Fig. 2). Only very light pressure on the lever is required. This engages the rear roller and the machine will move forward.
Adjustment instructions
Height of cut
The cutting height is raised by turning the adjusting knob (B Fig. 3) in a clockwise direction. To cut lower, reverse procedure.
When adjusting for low cutting, do not set mower so low that the weight of the machine is taken on the bottom blade instead of the front roller. This would affect cutting, and also place excessive load on the engine.
Warning. Before making adjustments to the cutter or chains, remove spark plug lead to avoid accidentally starting the engine.
Cutter setting
The cutter is set correctly when it is lightly touching bottom blade along its full length. Hard bearing or uneven setting causes excessive or uneven wear on cutting edges and also places undue load on the engine.
Before adjusting, lay the machine back with the handles on the ground, making sure the petrol tap (17″ and 20″ models) is “off”. To adjust cutting cylinder, release clamp nuts (C Fig. 4), both sides of mower. Cutter is set closer to the bottom blade by turning down (clockwise) the adjusting screws (D Fig. 5) until cutter blades just contact bottom blade. If the cutter bears too hard on the bottom blade turn the adjusting screws back at least a full turn and again carefully screw down until correctly adjusted. Retighten clamping nuts (C Fig. 4).
There are three Model 45 books on this site and they do not all agree on this. This one (1968) and the later Rover, Scott Bonnar operating instructions both say turn the adjusting screws down, clockwise, to close the gap; the 2005 Rover Mowers Limited owners manual says anti-clockwise. Work to the book that matches your machine, and confirm the result with the newspaper test rather than trusting the direction.
Cutter chain adjustment
Slacken nut (E Fig. 3). Move nylon chain adjuster to give correct chain tension and retighten nut. When correctly adjusted chain should be slightly slack and not tightly stretched.
Clutch and drum chains
Both chains are adjusted by loosening two nuts (G see Figs. 3 & 6), and moving this sprocket upwards which tightens both chains simultaneously. After retightening nuts some slackness should be felt in each chain.
Deflector
Depending on cutting conditions e.g. wet grass, dry grass, high wind velocity etc., it may be necessary to alter the angle of deflection into the grass box.
This is effected by loosening the thumb screws (H Fig. 5) each side of the machine and moving the deflector plate in the desired direction — move upwards to throw the grass higher and longer, or downwards to throw the grass lower and shorter. Retighten screws after adjustment.
Clutch cable adjustment
The clutch operating pressure can be increased by releasing the lock nut and screwing the threaded adjuster (J Fig. 6) outwards a few turns and retightening lock nut. This is necessary only if the unlikely condition of clutch slip with loss of propulsion should occur.
Handle adjustment
Slacken 4 nuts (K see Figs. 7 & 8) sufficiently to allow handle to be moved up and down. Re-tighten with handle in selected position.
The upper handle may be folded down by removing bolt (L Fig. 7). Use extreme care not to permanently bend clutch and throttle cables.
Lubrication
Occasionally oil at the following points:
- Cutter Ballraces (M Fig. 9) each end — Oiler.
- Engine Shaft Bearing (P Fig. 9)
- Engine Clutch (R Fig. 9)
- Driving Drums — pre-lubricated, no further attention required.
- Driving Drum Bearings — pre-lubricated, no further attention required.
- Front Roller (S Fig. 4) each end.
- Chains — for good service, chains should be occasionally slightly oiled.
General
This mower is constructed of first-class materials, and will give longer and more efficient service if kept clean. After cutting, and before putting machine away, wipe blades down with an oily rag.
Check nuts occasionally to see that they are not loose.
To obtain the best results from your mower, the cutter should be sharpened and set at least once a season. This can be arranged through any of our Branches or distributors.
Guarantee (as printed)
Scott Bonnar mowers are manufactured under close supervision and to the highest standards, and all precautions which are usual and reasonable have been taken to secure excellence of materials and workmanship.
The Manufacturers undertake to replace parts, free of charge, which fail through faulty materials or workmanship, within six months from date of purchase, provided such parts are returned to us, carriage paid, for examination.
This guarantee extends only to the original Purchaser from the Manufacturers or their authorised Agent. It does not cover the engine, the guarantee for which is as laid down by the engine manufacturer.
Conditions of guarantee
Any labour charges incurred under guarantee are the owner’s responsibility, and must not be charged to the manufacturer.
The Manufacturers will not accept liability for any loss, damage or accident directly, indirectly or consequently suffered by the purchaser, operator or any other person or to property as a result of such faults whether due to defective materials or workmanship, or otherwise.
This guarantee does not apply to defects which, in the opinion of the Manufacturers, are caused by accident, wear or tear, misuse or neglect, or by interference with the construction of the machine as completed by the Manufacturers.
Note — Items such as cleaning of spark plugs and carburettor jets, adjustment of cutters, etc., are not covered under this guarantee. While the services of our representatives are available to carry out minor adjustments, a charge is made to cover travelling time involved.
This guarantee is reproduced for historical completeness only. It expired with the original purchaser decades ago and confers no rights today.
Distributed throughout Australia by (as printed)
- New South Wales: 357 Liverpool Road, Ashfield · Phone 798 0222
- Victoria: 265 Huntingdale Rd., Huntingdale · Phone 544 1277
- South Australia: 33–47 Holland Street, Thebarton · Phone 57 9155
- Queensland: 27 Ipswich Road, Woolloongabba · Phone 91 2676
- Tasmania: B. J. Electrics Pty. Ltd., 42 Wellington St., Launceston · Phone 2 1865
- Western Australia: 104 Belgravia Street, Belmont · Phone 65 1288
Transcribed from Scott Bonnar folder 1941452 (8/68), manufactured at 33–47 Holland St., Thebarton, South Australia. The scanned pages in the viewer above are the authoritative source.