H37i
Maintenance Instructions
Checking and Servicing
61
4. If the blade cutting edge is
dull or nicked,
it
should be sharpened. Remove blades for
sharpening by grasping the end of the blade
using a rag or a thick, padded glove, while
loosening and removing the bolt and washer
that mount the blade.
5. Grind cutting edge at the same bevel as the
original. Sharpen only the top of the cutting
edge to maintain sharpness.
NOTE:
Blades can be sharpened with an
electric blade sharpener, conventional electric
grinder, or a hand file.
CAUTION
ALWAYS wear eye protection and gloves
when sharpening a blade.
Sharpen at Original
30° Angle
Intersection
Wear Area
Do Not Grind or
Sharpen on Underside
30°
Wing Tip
Mower Blade Profile for Sharpening
6. Check blade balance by positioning the blade
horizontally
on a blade balancer or use a nail
or shaft through the center hole. If either end
of the blade rotates downward, grind (remove)
metal on that end until the blade will balance.
The blade is properly balanced when neither
end drops. Balance of a blade is generally
main tained by removing an equal amount of
material from each end of the blade when
sharpening.
Blade Balancer
Blade Balanced on Magnetic
Wall-Mounted Balancer
7. Mount the blade with wing tips pointing up into
the housing. For
gear-driven decks
reinstall
the blade, washer, lock washer, and nut.
Tighten the nut to 60 lb·ft (81 N·m).
For
belt-driven decks
reinstall the spacer (if ap-
plicable), blade, washer, and bolt.
Tighten
the bolt to 70 lb·ft (95 N·m).
Drive Belts
Raise the body and inspect the condition of the
four (4) drive belts
after every 25 hours
of opera
-
tion–engine/PTO drive (3), ground drive (1). Also
remove the belt cover on the mower deck and
check the blade drive belt. If the belts show
signs
of cracking or deteriorating,
the belts should be
replaced.
Refer to
Drive Belts on page 64.
Spark Plugs
Every 200 hours
of operation, remove the spark
plugs, inspect, clean, and reset the gap (or replace
with
new plugs
). Before removing the spark
plugs, clean the area around the base of the plugs
to keep dirt and debris out of the engine. Clean
spark plugs with a wire brush. DO NOT use an
abrasive grit type cleaner. If the electrodes are
burned short or pitted, replace the plug (refer to
Specifications on page 3
for the proper type of
replacement plug). Check spark plug gap with a
wire-type feeler gauge and set the gap to 0.030 in.
(0.76 mm). Reinstall and tighten to 20 lb·ft
(27 N·m). Both spark plugs should be replaced
yearly.
Ignition Wires
Good preventive maintenance calls for complete
replacement
of spark plug wires
every two (2)
years.
