Dennis G680 User manual

G680WG_Instructions.doc
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DENNIS G680
MOWER
INSTRUCTION MANUAL
Publication No.
G680ins(Wargraves 3 Roller section).doc
DENNIS, Ashbourne Road, Kirk Langley, Derby, DE6 4NJ
Telephone: [phone]
Fax: [phone]
e-mail [email protected]
e-mail [email protected]

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C O N T E N T S
Page
Introduction 2
Description 2
Important Safety Instructions 3
Machine Familiarisation-CONTROLS 5
Operating Instructions 6
Engine Information 7
General Adjustments 8
Routine Maintenance 11
General Lubrication 13
Storage 14

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DENNIS 27" CYLINDER MOWER MODEL G680
INTRODUCTION
The reliability and quality of performance of the DENNIS G680 depends upon some
simple care maintenance carried out regularly. This manual has been prepared to allow the
user to carry out all such work.
It is advisable to read the instructions carefully. Proper care and attention will enable the
machine to give a continuous, satisfactory, and reliable service.
Failure to carry out regular lubrication and maintenance as outlined in this manual may
render any guarantee or warranty invalid.
In the case of any difficulty, or if further information or advice is required, our Service
Department is always at your call. In the interests of speed and accuracy of information
please quote the serial numbers of the machine and engine when making enquiries.
For the mower, this is to be found on a plate attached to the side frame. The engine
number is stamped on either the crank case or the gear casing facing towards the front of
the machine.
DESCRIPTION
Manufactured with a 27" (68cm) cutting width this mower is powered by a 8 h.p. air
cooled single cylinder four stroke petrol engine ( Kubota ). The rear roller and cutter are
controlled independently via belt clutches operated from the console on the upper handlebar
. A parking brake is fitted for added safety when working on sloping ground.
In the design of the machine, special attention has been given to the importance of easy
service and maintenance with the construction based on a sectional assembly system.
These are the Engine Unit, the Rear Roller Unit, and the Front Roller Unit, each of which
can be readily removed individually from the main Frame Chassis Unit.

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IMPORTANT SAFETY INSTRUCTIONS
In order to operate the machine safely please follow these Health and Safety guidelines.
TRAINING
Read the instructions contained in this manual with care. If you are in any doubt please ask
your employer or contact us direct at DENNIS. Be familiar with the controls and the
proper use of the equipment.
On the job training courses are available from Dennis. Contact the factory or you dealer for
details.
Never allow children or people unfamiliar with these instructions to use the mower. Local
regulations or insurance may restrict the age of the operator.
Never mow while people, especially children, or pets are nearby.
Keep in mind that the operator or user is responsible for accidents or hazards occurring to
other people or their property.
PREPARATION
While mowing always wear substantial footwear and long trousers. Do not operate the
mower in barefoot or in open sandals.
Thoroughly inspect where the equipment is to be used and remove all stones, sticks, wire,
bones and other foreign objects.
WARNING:-Petrol is highly flammable and will damage grass if spilt.
A) Store fuel in containers specifically designed for this purpose.
B) Refuel out doors and do not refuel whilst smoking.
C) Add fuel before starting the engine. Never remove the cap of the fuel tank or
add petrol while the engine is running or when the engine is hot.
D) If petrol is spilled do not attempt to start the engine but move the machine
away from the area of spill and avoid creating any sources of ignition until the
vapours have dissipated.
Replace damaged or faulty silencers.
Before using the machine always inspect the safety devices including the cut off switch and
the blades for excessive wear or damage. Replace if necessary.

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OPERATION
Do not operate the engine in a confined space where dangerous CARBON MONOXIDE
fumes can collect.
Mow only in daylight or good artificial light.
Avoid operating the machine in wet grass where feasible.
Always be sure of your footing on slopes.
Walk. Never run.
Walk across the face of slopes, never up and down.
Exercise extreme care on slopes when changing direction.
Do not mow excessively steep slopes. MAX 20% slope for engine.
Use extreme caution when reversing or pulling the machine towards you.
Stop the blades if the mower has to be tilted for transportation when crossing surfaces other
than grass and when transporting the mower to and from the area to be mown.
Never operate the mower with defective guards or shields or without the safety devices, for
example without the deflector plate or grassbox in place.
Do not change the engine governor settings or overspeed the engine.
Disengage all blades and drive clutches before starting.
Start the engine carefully following the instructions with feet well away from the blades.
Do not tilt the mower when starting the engine.
Do not put hands or feet near or under rotating parts. Keep clear of the discharge opening
at all times.
Never pick up or carry the mower while the engine is running.

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IMPORTANT INFORMATION
Please read all the details in this section and familiarize yourself and all machine operators
with the contents.
CONTROLS
All controls with the exception of the choke and starter chord are located on the handlebar
console. Decals indicate the location and operation of each.
SAFETY LEVER
Located on then right hand side of the upper handlebar this L shaped black lever is made
from flattened tubular section. It operates an electrical contactor within the console which
interlocks other functions such as cutter clutch and parking brake. This lever is spring
loaded to return to off position when released.
BALE BAR
Located closest to the operator on the upper handlebar assembly this black lever made from
flattened tubular section goes across the width of the handle and is pivoted on both sides. It
operates, via a spring loaded cable assembly, the roller clutch mechanism which is located
under the guard adjacent to the engine. The lever is designed to engage the safety lever
when it is operated (pushed forward), and releases the safety lever when let go. The spring
returns it to the off position. The machine will move forwards when the bale arm is pushed

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towards the upper handlebar and can be "clamped " under ones hand onto the handlebar for
comfortable operation.
CUTTER CLUTCH
Located on the left hand side of the console with a red lever. Forwards to engage, back to
disengage. The lever is interlocked with the safety lever and the engine will cut out if
engaged without firstly operating the safety lever. The lever operates, via a spring loaded
cable, the cutter clutch mechanism located under the chaincase on the left sideplate.
PARKING BRAKE
Located in the centre of the console as a red lever. Forwards to engage the brake, back to
release. The lever system is interlocked with the safety lever and the engine will cut out if
the safety lever is operated with the parking brake on.
The lever operates, via a cable, a braking mechanism locate under the guard next to the
engine.
THROTTLE
Located on the right hand side of the console as a black lever. Forwards for low revs,
backwards for more. The mechanism is a piano wire type. Do not overstrain.
ON/ OFF SWITCH
Located on the right hand side of the console facing the operator position. This switch
isolates the engine and cuts off the spark. Ensure it is in the ON position before attempting
to start the engine and for added safety put to OFF position when the machine is stopped
for added safety.
OPERATING INSTRUCTIONS
PREPARATION FOR USE
Before commencing ensure the turf is free from stones or other obstructions which may
damage the cutter unit.
Set the height of cut to the required level (see page 9)
Check the engine.
Fill the fuel tank 3/4 full with unleaded petrol.
Always check the oil levels of the machine prior to commencing.
Full details are given in the ENGINE Manual, which accompanies this book.
This should be read carefully before starting the engine.
A daily check is recommended.
(Recommended grade oil is SAE 10-40 Multigrade).
Disengage the cutter clutch. This is a red lever located on the handle bar console on the left
hand side when at the operators position.
Set the throttle control on the handlebars console to the idle position.

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Ensure toggle on /off switch to ON position. This is situated on the right hand side of the
handlebar console facing the operator.
The engine may now be started according to the manufacturer's instructions.
TO COMMENCE CUTTING
Once the engine is running and the choke has been turned off set the throttle to middle
position.
Disengage the PARKING BRAKE , engage the SAFETY LEVER with your right hand
and engage the CUTTER CLUTCH with the left hand. The cutter will commence rotating.
Push the BALEBAR forwards to the handlebar and the machine will move forwards. A
slow engagement is possible to avoid the machine skidding or jolting forwards.
It is possible to hold the BALEBAR against the handlebar with one hand as the balebar
clamps the safety lever in the on position.
When it is required to disengage the roller clutch use your right hand to hold the safety
lever in the on position otherwise the engine will stop if the cutter clutch is still engaged.
Practice with the controls will soon bring confidence in operation.
Accidental release in the case of a fall or slip will automatically stop the machine and, if the
cutter clutch was engaged the engine will stop.
TRANSPORT (disengaging the cutter drive)
To ensure the safety of operator and machine we strongly recommend disengaging the
cutter drive when transporting under power between sites.
ENGINE INFORMATION
The G680 is fitted with a Kubota GH250 petrol engine. single cylinder, overhead valve, 4
stroke, forced air cooled engine. For full specifications please refer to the manufacturers
instruction manual included.
Starting the engine:
Once the preparatory steps have been completed as outlined on page 5 the engine may be
started. (see manufacturer operating manual for full details).
Switch on the fuel tap.
Switch the handlebar console cut off switch to ON.
Set the throttle control to a half open position.
Shift the choke lever to the appropriate position (Kubota engine set to
START :
The choke is not required if the engine is warm or the air temperature high.
Grasp the recoil start handle until resistance is felt, then pull it with force.
Do not allow the starter grip to snap back against the engine. Return it gently
to prevent damage to the starter.
Once the engine is started gradually `open' the choke lever (move the lever
towards the RUNNING, or OPEN position). Warm-up running of 3-5

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minutes is recommended.
Stopping the engine:
Set the throttle control to the `closed' position.
Switch the handlebar console cut off to OFF
Close the fuel tap.
ENGINE MAINTENANCE (See manufacturer instructions for full maintenance
details)
Check oil level Daily
Change engine oil After 50 working hours (Initial change after 20 hours)
Clean spark plug Every 100 hours
Clean air filter Every 50 hours
Overhaul Every 500 hours
GENERAL ADJUSTMENTS
The DENNIS G680 is supplied with a tool wallet containing set spanners and a plug
spanner. Sizes for adjustment are quoted in mm.
SHEAR BLADE ADJUSTMENT.
Correct setting of the shear blade is essential to effective cutting of grass. If the set is too
far away it will result in bruised grass and poor results. If set too hard on it will cause
excessive wear on the drive system and "dull’ the bottom blade and cylinder because of
heat build up. Never operate the cylinder for more than a few seconds without cutting
grass. Never attempt any adjustment or maintenance whilst the engine is running.
Beware – Cylinders and bottom blades are sharp, wear gloves to protect your hands and
fingers.
The cylinder cassette is set in situ in the machine. We strongly recommend that the spark
plug lead is removed for added safety. Switch off the fuel before tipping machine back to
avoid any chance of spillage.
The adjustment is facilitated by turning the spring loaded bolts on either side of the cutter
cylinder in the direction indicated by the decals. The shear blade carrier is pivoted in the
sideplate and as the "ear " is moved back the blade gets closer to the cylinder. Adjust until
both sides are just in contact with the cylinder. Do not tighten one side excessively as this
will cause twist in the bottom blade.

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The cutting cylinder should just brush against the shear blade. The correct setting is an
audible whisper of cylinder moving against the shear blade -we suggest gloves be worn for
this part of the operation. The unit should just cut 80 g.s.m. (photocopy paper) along its
length. Heavy contact of the blade and cylinder will result in rapid wear.
SETTING FOR HEIGHT OF CUT
Always stop the engine before adjusting the height of cut. Failure to do this may result in
severe injury.