Scott Bonnar Model 45 Series Reel Mower — Operating Instructions

The Rover, Scott Bonnar operating instructions for the Model 45 series reel mower — preparation, deflector and height of cut, starting and propelling, cutter setting by the newspaper test, chain and clutch cable adjustment, lubrication, and fitting the optional edge cutting attachment. Note this book turns the cutter adjusting screws clockwise to close the gap; the later 2005 Rover manual says anti-clockwise.

• ModelsModel 45 Series (Rover, Scott Bonnar era)
• Pages8
• Publication1942892

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Full text of this manual

A full transcription of the Scott Bonnar Model 45 Series Reel Mower operating instructions, publication 1942892 — the Rover, Scott Bonnar book, from when the company still traded out of Holland Street, Thebarton.

There are three different Model 45 books on this site and it is easy to pick up the wrong one. This is the middle one. The earlier Scott Bonnar Operating and Maintenance Instructions covers models 450415, 450423 and 450431; the later Rover Mowers Limited owners manual covers 45048 and 45148 and carries the same publication number as this one with a revision letter (S1942892 Rev. I). They do not all give the same cutter adjustment direction — see the note under Cutter setting below.

Preparation

When the mower is removed from the carton the upper handle will be in a folded position. Pivot the handle into the upright position and secure it in this position with the clamp screw and nut provided. If folding the handle use extreme care not to permanently bend clutch and throttle cables.

Handle height can be adjusted by slackening nuts (A) on both sides of mower to allow the handle to be pivotted up or down. Re-tighten nuts with handle in selected position.

NOTE — Only limited adjustment may be achieved on mowers fitted with a large capacity fuel tank.

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 grassbox.

This is effected by loosening the thumb screws (A) each side of the machine and moving the deflector plate in the desired direction — move upwards to throw the grass higher and further, or downwards to throw the grass lower. Re-tighten screws after adjustment.

Height of cut

The cutting height is raised by turning the adjusting knob (B) 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.

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 oil. SAE 30 or 20 W-50 is suitable.
2. Fill fuel tank — use standard grade petrol (do not mix oil with petrol).
3. Ensure that the spark plug lead is connected.

Starting and operating

1. Move the throttle control lever into ‘start’ position. Hold upper handle with left hand and pull the starter cord with a long smooth action without jerking.
2. When engine has started adjust throttle lever to obtain an engine speed suitable to the operation of the mower.

To propel the mower

3. Engage the cutter by turning the cutter clutch lever upwards.
4. Gently squeeze the traction clutch control. Only light pressure on the lever is required. This engages the rear roller and the machine will move forward.

The numbering runs 1–4 straight through the four photographs on that page; that is how the original prints it.

To empty grasscatcher

• Reduce engine speed to ‘slow’.
• Always stop the cutter by operating the cutter clutch lever.
• NEVER attempt to clear grass from the grasscatcher or cutter area if the cutter is rotating.

Stopping the engine

• Disengage the cutter clutch.
• Move throttle control to ‘stop’.

Adjustments

WARNING — Before checking or making adjustments, [remove] the lead from the spark plug to avoid accidentally start[ing the] engine.

When checking the setting, keep fingers clear of the cu[tting] edges while rotating the cutter by hand. When mower is t[ilted] back for adjustment, petrol leakage could occur if the tank is near full. Drain off petrol or use a container to catch spill.

Cutter setting

If unsatisfactory cutting is evident — check the setting. […] occurs it will become necessary to adjust the cutter clo[ser] to the bottom blade.

The right-hand edge of this page has been trimmed off in the scan. Words in square brackets above are obvious from context; the phrase marked […] — a few words along the lines of “as wear occurs” — is genuinely gone and has not been guessed at.

The cutter is correctly set when it LIGHTLY touches the bottom blade along its FULL length. Hard bearing or uneven setting causes excessive or uneven wear on the cutting edges and also places undue load on the engine.

To check the setting, tilt the mower back on the handles. Hold a narrow strip of newspaper between the bottom blade and the cutter, while rotating the cutter carefully by hand. The setting is correct if the paper is cut or folded when tested at several positions along the full length of the blade. However, the cutter must be free to rotate without binding.

Adjustments can be made simply by the following procedure:—

1. Release the clamping nuts (C) both sides of mower.
2. To set cutter closer to the bottom blade, turn down (clockwise) the adjusting screws (D) on each side until the cutter just contacts the bottom blade at both ends.
3. If cutter bears too hard on the blade, turn the adjusting screws back at least a full turn and again carefully screw down each, a little at a time, until correct contact is achieved.
4. Retighten the clamping nuts securely.
5. Test setting with paper strip.

Resetting the cutter will affect the chain tightness and this should be checked. Refer to chain adjustment.

If the paper test cannot be achieved satisfactorily, the blades may be blunt or worn unevenly and sharpening will be necessary. This service is available through any Scott Bonnar branch or authorised service dealer.

Check which book you are holding before you turn a screw. This one and the 1968 Scott Bonnar book both say turn the adjusting screws down, clockwise, to bring the cutter closer to the bottom blade. The 2005 Rover Mowers Limited manual says anti-clockwise for the same result. All three are reproduced exactly as printed; the adjusting hardware changed over the model’s life, so work to the book that matches your machine — and in every case confirm the result with the newspaper test rather than trusting the direction.

Cutter chain adjustment

Slacken nut (E). Move nylon chain adjuster to give correct chain tension and retighten nut.

Clutch and drum chains

Both chains are adjusted by loosening two nuts (G), and moving the large chain sprocket upwards which tightens both chains simultaneously. Hold the chain sprocket so that both chains are near taut and retighten nuts.

NOTE — Correctly tensioned chains should be slightly slack and not tightly stretched.

Clutch cable adjustment

The clutch operating pressure can be increased by releasing the lock nut (A) and screwing the threaded adjuster (B) 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.

Maintenance — lubrication

The same grade of oil as used in the engine is suitable.

• (A & B) These bearings are sealed and grease packed and do not require any additional lubrication.
• (C) Clutch thrust pad — apply oil as required.
• (D) Front roller — apply oil to shaft as required.
• (E) Height adjust knob. Remove plastic plug — few drops each season.
• Drive chains. Twice seasonally, use small brush and apply oil lightly over chains.

Air cleaner

For detailed cleaning instructions refer to the engine operating manual.

Clean frequently in dry and dusty conditions as the filter can become clogged with fine grass particles. Normally clean twice seasonally.

Do not use the filter element dry, as fine dirt will pass through the pores and into the engine. After cleaning and re-oiling the element, squeeze out as much oil as possible.

Carburettor

No maintenance is required other than brushing away accumulated dirt and grass from the linkages.

General

Occasionally check that grass particles are not blocking the flow of cooling air through the starter screen or engine fins. Periodically check the nuts and bolts for tightness. The mower will give longer and more efficient service if kept clean of grass and dirt build up.

Correct cutter setting is vital — proper care means less wear

1. Ragged, uneven cutting caused by poor cutter setting.

If your mower is doing a ragged uneven job of mowing it does not necessarily mean that the blades need sharpening. In most instances it simply means that the cutter needs re-adjusting.

With use, the cutter and bottom blade gradually wear away from each other, causing the grass to be dragged through and not cut cleanly. The blades maintain a better edge so long as they are very lightly touching.

The action of a Scott Bonnar reel type mower produces a scissor-like cut and therefore the cutter adjustment is all-important to the finished appearance of the lawn.

2. Smooth, even cutting effected by correct cutter setting.

From time to time depending on frequency of use and conditions of your lawn area, your mower will require adjustment of the cutter setting. You will benefit by becoming conversant with the simple procedure required to maintain peak cutting efficiency.

THE CORRECT PROCEDURE FOR CUTTER ADJUSTMENT IS SET OUT IN THIS BOOK UNDER “CUTTER SETTING”.

3. The front roller has nothing to do with the adjustment of the cutting blades.

It merely serves as the adjustment for HEIGHT of cut, allowing the cutter to pass across the grass at the desired height of cut.

The two diagrams on this page show the difference: a visible gap between cutting cylinder and bottom blade (wrong), against cutting cylinder and bottom blade lightly touching (right).

Fitting instructions for the edge cutting attachment

(The edging attachment is an optional extra.)

1. Remove chain cover and push out red plastic plug. Remove nut located behind this plug. Replace cover. Screw on extended pulley. Tighten by using a bar through hole in the shank.
2. Bolt edge cutter support bracket to mower sideframe with curved slot in bracket towards the front. Bolt holes are provided in sideframe near front of mower.
3. To attach the cutter assembly to the supporting bracket, remove clamping nut and washer from cutter assembly.
4. Enter the clamping bolt in the curved slot and the fixed pivot pin in the small hole. Replace nut and washer finger tight to hold cutter assembly in place.
5. Loop drive belt over the blade, and rotate blade by hand to pass belt into the cutter pulley.
6. Fit belt over top pulley and set blade to required depth of cut by pivotting cutter. Tension belt by sliding cutter forward on pivot block. Tighten clamping nut.

It is not necessary to remove the cutter when mowing. It can be pivotted upwards clear of the ground with belt looped around the guard.

The original sets these steps out as unnumbered paragraphs beside two photographs; they are numbered here in printed order so the sequence is easier to follow.

Power lawnmower safety precautions

1. Know your controls. Read the owner’s manual carefully. Know how to stop engine quickly in any emergency.
2. Make sure the lawn is clear of sticks, stones, bones, wire and debris.
3. Stop the engine and disconnect spark plug wire before checking or working on the mower.
4. Check all nuts, bolts and screws. Use only replacement parts made and guaranteed by the original manufacturer of your mower.
5. Add fuel BEFORE starting engine. Avoid spilling petrol and do not fill the tank while engine is running or while you are smoking.
6. Do not mow barefoot or in open sandals.
7. Disengage all cutter and drive clutches before starting.
8. Do not operate engine in a confined space where exhaust fumes (carbon monoxide) can collect.
9. Stop the engine whenever you leave the mower.
10. Stop the engine before pushing mower across gravel drives, walks or roads.
11. Do not allow children or people unfamiliar with these instructions to use the mower.
12. On slopes or wet grass, be extra careful of your footing.
13. Do not over-speed the engine or alter governor settings.
14. Store fuel in a cool place in a container specifically designed for the purpose. In general, plastic containers are unsuitable.
15. Never attempt to clear grass or obstructions from a mower while the engine is running.

Warranty (as printed)

ROVER, SCOTT BONNAR 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 ROVER, SCOTT BONNAR 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 ROVER, SCOTT BONNAR SHALL EXTEND ONLY TO REPAIRING OR REPLACING SUCH PART AT ITS SERVICE BRANCHES OR AT THE PREMISES OF AN AUTHORISED SERVICE REPRESENTATIVE.

Please note the following 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 Rover, Scott Bonnar 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)

Scott Bonnar, 33-47 Holland Street, Thebarton, Adelaide, South Australia, 5031. Telephone: 43 9155.

• South Australia: Rover, Scott Bonnar, 33-47 Holland Street, Thebarton 5031. Telephone: 43 9155
• Western Australia: Rover, Scott Bonnar, 104 Belgravia Street, Belmont 6104. Telephone: 277 1288
• Tasmania: P.O. Box 248C, Hobart 7001. Telephone: 72 3177. 43 Cypress Street, Launceston 7250. Telephone: 31 2282
• Queensland: Rover, Scott Bonnar, Cnr. Ferret & Links Ave., Eagle Farm, Brisbane 4007. Telephone: 268 2571
• North Queensland: Rover, Scott Bonnar, Railway Avenue, Railway Estate, Townsville 4810. Telephone: 72 3714
• New South Wales: Rover, Scott Bonnar, 6 Epic Place, Chester Hill 2162. Telephone: 645 3555
• Victoria: Rover, Scott Bonnar, 28 Treforest Drive, Clayton 3168. Telephone: 543 3377

None of these offices still trade, and the telephone numbers predate area codes and eight-digit numbering — they are transcribed as printed, for dating the book rather than for ringing.

The back cover of the scanned copy carries the original owner’s handwriting: “Briggs & Stratton 3 HP at 3600 RPM = 127 CC” and “Model 45, Serial No. 18923”. That is a private annotation, not factory text, but it does tell you what engine one of these machines left the factory with — and the “3 HP” Briggs & Stratton badge is visible in the starting photograph in the viewer above.

Transcribed from Rover, Scott Bonnar operating instructions, publication 1942892. The scanned pages in the viewer above are the authoritative source.