Maintenance - Murray MP450 Operator's Manual

Before Operation Of The Mower
WARNING: Check the condition of the grass bag
for wear or deterioration. If worn or damaged,
replace the parts only with approved factory
replacement parts.
To completely fill the grass bag, operate the engine with the
throttle control (if equipped) in the fast position.
To completely fill the grass bag (if equipped) operate the
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engine with the throttle control (if equipped) in the fast
position.
Make sure the grass bag (if equipped) is properly
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mounted.
Check the condition of the grass bag for wear or
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deterioration. If worn or damaged, replace the parts only
with approved factory replacement parts.
How To Adjust The Height Of Cut
WARNING: The blade will rotate when the engine
runs. Before you change the height of cut,
disconnect the spark plug wire and keep it away
from the spark plug.
Models With Individual Wheel Adjusters - Figure 16
To change the height of cut, move the position of the adjuster
arm (A) at each wheel as follows.
1. Disengage the adjuster arm (A).
2. Move the adjuster arm to another position.
3. Make sure that each adjuster arm is in the same position
so that the mower will cut level.
Models With Single-Lever Adjuster - Figure 17
To change the height of cut, move the position of the adjuster
arm (B) as follows.
1. Disengage the adjuster arm (B).
2. Move the adjuster arm to another position.
How To Empty The Grass Bag - Figure
WARNING: Before you remove the grass bag, stop
the engine. Before you remove any grass from the
mower housing, disconnect the spark plug wire and
keep it away from the spark plug.
1. Raise the rear door (F). See Figure 9.
2. Hold the handle (G) of the grass bag. Lift the frame
assembly (H) over the rear door pivot rod (I).
3. Empty the grass from the grass bag (E). See Figure 19.
How To Use As A Mulcher - Figure
WARNING: Before you install or remove the
mulcher plug, disconnect the spark plug wire and
keep it away from the spark plug.
1. For mulching grass, remove the grass bag (I) and the side
discharge chute (M) from the mower. See Figure 1.
2. Raise the rear door (B) and install the mulcher plug (A)
into the rear discharge opening. See Figure 10.
Mowing Tips
Some models have an optional mulcher plug. If the mulcher
plug is installed, the grass is finely cut and will easily recycle.
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Because the nutrients are returned to the soil, the lawn will
need less fertilizer.
The following tips will increase performance and improve the
appearance of the lawn.
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To improve the quality of cut, try the following:
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Maintenance

Engine Maintenance
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Illustrations and pictorials begin on page 2.
Use the following maintenance section to keep your unit in
good operating condition. Before you start the engine, read
this manual and also the Operator's Manual for the engine.
All the maintenance information for the engine is in the
Operator's Manual for the engine.
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Engine Tipping - Figure
NOTICE: Do not tip the engine with the spark plug down.
When you service the engine, inspect the blade, or clean the
bottom of the mower housing; make sure to always tip the
engine with the spark plug up. Transporting or tipping the
engine with the spark plug down will cause the following.
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Lubrication
1. For maximum performance, lubricate the wheels and all
2. To lubricate the engine, refer to the Operator's Manual for
NOTICE: Do not lubricate the engine stop cable. Lubricants
will damage the cable and prevent the cable from moving
freely. Replace the cable if bent or damaged.
The grass must be dry. If the grass is wet, it will be difficult
to cut and cause heavy clumps of grass.
The grass must not be too tall. The maximum height to
effectively cut is 9.8 cm. Set the height adjusters so that
only the top third of the grass is cut.
If the grass is more than 9.8 cm high, two mowings will be
necessary. For the first mowing, set the height adjusters in
the highest position. Then, lower the height adjusters for
the second mowing.
Keep a sharp edge on the blade. A blade that is not sharp
will cause the ends of the grass to become brown.
Clean the bottom of the mower housing. If grass and other
debris accumulate on the bottom of the mower housing,
performance will be reduced.
raise height of cut
cut more frequently
operate at a slower ground speed
reduce width of cut
change direction
mow a second time
WARNING: Before you make an inspection,
adjustment, or repair, disconnect the spark plug
wire and keep it away from the spark plug.
hard starting
engine smoking
spark plug fouling.
oil or fuel saturation of the air filter
pivot points with engine oil every 25 hours.
the engine.
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