33
Test Procedure
1. Start engine and run for 5 minutes at 3/4 throttle, to
warm hydraulic fluid.
2. Drive the machine to a clear and level open area such
as a driveway.
Important
There should be at least 10 feet of clear
area in front of the machine.
3. Loosen the quick release levers and push the reference
bar forward to the “FAST” position. Lock the quick
release levers to secure the reference bar.
4. Move throttle control to 3/4 throttle.
5. Quickly push the upper control bar against the
reference bar. The front caster wheels should almost
lift off the ground. If front caster wheels lift the off the
ground , the machine is too aggressive and adjustment
is required.
6. Move the engine throttle to the “FAST” position.
7. Quickly push the upper control bar against the
reference bar. The front caster wheels should lift
approximately 1 inch off the ground. If front caster
wheels lift the off the ground more than 2 inches, the
machine is too aggressive. Adjustment is required.
8. If the machine accelerates slowly, and the front caster
wheels do not lift off the ground, the machine is too
un–responsive. Adjustment is required.
Adjustment Procedure
The by–pass valve should be adjusted to deliver best
performance for the size (weight) mower you have.
The following values can be used as initial settings for
different size mowers:
52 in. (132 cm)
1/2 turn out
44 in. (112 cm)
1 turn out
36 in. (91 cm)
1–1/6 turn out
1. Loosen large jam nut several turns (Fig. 35).
2. Gently close by–pass valve (Fig. 35).
Important
Do not over–tighten valve or needle and
seat may be damaged. Do not exceed 50 inch pounds to
close valve.
3. Open by–pass valve 1/2 turn (Fig. 35).
4. Tighten jam nut to lock the adjustment (Fig. 35).
5. Repeat “Test Procedure” to check for proper operation.
Important
By–pass valve adjustment is very sensitive,
do not adjust more than 1/6 turn (one flat) at a time.
6. If the machine is too aggressive or tends to jump
forward, the valve needs to be opened further.
7. If the machine is slow to respond, the valve needs to
be closed further.
8. Repeat “Test Procedure” to check for proper operation.
Re-adjust the by–pass valves until proper performance
is achieved.
1
2
m–5209
Figure 35
1.
By-pass valve
2.
Jam nut
Hydro Linkage Adjustments
Perform the following linkage adjustments when the
machine needs maintenance. Perform steps Adjust Speed
Control Linkage through Adjust Tracking. If adjustment is
needed, do them in the order that they are listed.
Adjust Speed Control Linkage
1. Stop engine and wait for all moving parts to stop.
2. Move the speed control lever (located on the console)
to the full forward position.
3. Check the orientation of the tabs on the ends of the
speed control crank. These tabs should be pointing
straight down at the 6 o’clock position approximately
(Fig. 37).
4. Adjust the threaded yoke at the bottom of the speed
control linkage until the tabs are at the 6 o’clock
position (Fig. 37).
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