Operation 11
20944 (Rev. 2/3/2006)
Cutting Height Adjustment
Keep all persons away from operator control
area while performing adjustments, service, or
maintenance.
■
Avoid very low cutting heights. Blades striking
the ground produces one of the most damaging
shock loads a mower can encounter. Allowing
blades to contact ground repeatedly, will cause
damage to mower and drive.
Before leveling unit that is equipped with pneumatic
tires, check air pressure. Follow manufacturer's guide-
lines on tire sidewall.
Level mower from side to side. Check by measuring
from mower frame to the ground at each front corner.
Adjust, using tractor 3-point arm leveling device. See
page 12.
Adjust cutting height with tractor 3-point arms and rear
caster wheel adjustment. The cutting height will be the
distance between the blade and the ground. The
blades are approximately 5" below the top of the
mower frame. To check cutting height, place a straight
edge along top edge of mower frame as shown in Fig-
ure 2. Measure from bottom of straightedge to the
ground at locations (A) and (B). Subtract 5" from mea-
surement (B) to determine cutting height.
For best mowing results adjust the front of the mower
slightly lower than the rear. Measurement at location
(A) should be at least 1/4" greater than location (B),
and not more than 1/2" greater than location (B).
Adjust the check chains, tailwheel and/or lower tractor
lift arms to maintain desired cutting height.
NOTE: Optional check chains and front gauge
wheels are available.
Before working underneath, raise mower to
highest position and block securely. Blocking up
prevents mower dropping due to hydraulic leak
down, hydraulic system failures, or mechanical
component failures.
Figure 2. Cutting Height Adjustment
on RM990-3 Mounted Mower
Cutting Height Adjustment with Front & Rear
Caster Wheel
Place the front and rear adjustment in corresponding
lettered holes. Refer to the chart for approximate cut-
ting height.
Figure 3. RM990-3 Cutting Height Adjustment with Front Caster Wheel
A
WARNING
A
WARNING
Hole No.
Approximate Cutting Height
A
1.00"
B
1.50"
C
2.00"
D
2.50"
E
3.00"
F
3.5"
Hole No.
Approximate Cutting Height
G
4.00"
H
4.50"
I
5.00"
J
6.00"
K
7.00"
L
8.00"
