Exmark NAVIGATOR NV640KC Operator's Manual page 34

Maintenance
1. Stop engine and wait for all moving parts to
stop.
2. Pull the speed control lever completely back to
the neutral position. The two steering levers
should be straight up and down (vertical). If
necessary, adjust steering levers by changing
the length of the link between the speed
control lever and the control arm on the end
of the steering control shaft (see Figure 17).
Figure 17
1. Loosen jam nuts here to
adjust linkage
• Set neutral:
1. Remove the electrical connection from the
seat safety switch, located directly in front of
the seat switch assembly.
2. The neutral adjustment must be made with
the drive wheels turning. Raise the frame and
place on jack stands so that drive wheels can
rotate freely. Temporarily install a jumper wire
across the terminals in the connector of the
wiring harness.
3. Start the engine.
4. Run the unit at least 5 minutes with the
speed control lever at full forward speed to
bring hydraulic system oil up to operating
temperature. Return speed control lever to
neutral (full rear) position.
5. To obtain the neutral position, adjust the
left and right pump control rod linkages that
connect the steering control to the pump
control arms until the wheels stop, or creep
slightly in reverse.
2. Steering levers should
be vertical
6. Adjust the left pump linkage by rotating the
tracking adjustment knob.
7. Adjust the right pump linkage by using
a wrench to turn the double nuts on the
assembly (see Figure 18)
1. Rotate tracking knob on
left side
8. Move the steering levers to the reverse
position. While applying slight pressure to
the levers, allow the steering levers to return
to neutral. The wheels must stop turning (or
slightly creep in reverse).
9. Stop engine and wait for all moving parts to
stop. Remove jumper wire from wire harness
connector and plug connector into seat switch.
10. Lower from jackstands.
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Figure 18
2. Rotate double nuts on
right side