NSS with eccentric plug
Neutral start switch
Switch
lock nut
Eccentric plug
Switch pin
Special lock nut
for eccentric plug
Eccentric plug
Switch pin
Special lock nut
for eccentric plug
Control
mounting
surface
View B-B
(switch and lock nut removed)
P104 150E
B
B
1. Hold the switch and eccentric plug from turning and use a 1
‑
1/8 inch wrench to loosen the lock nut.
Remove the neutral start switch.
W
Warning
Do not start the prime mover while the neutral start switch is removed from the control. Case
pressure will force the pin out of the eccentric plug, causing oil loss.
2. Note the slots on the eccentric plug for the adjustment tool. Hold the eccentric plug in place with the
adjustment tool, and loosen the lock nut with a 1-1/8 inch wrench.
3. Position the eccentric plug so the switch pin is offset toward the control mounting surface. This will
provide the best contact between the pin and the cam on the control shaft.
4. Hold the control shaft in its neutral position (in the center of the control shaft free-play area). Locate
the switch pin in the slot of the switch cam by turning the eccentric plug while checking the pin
position (depth) in the plug. When the pin engages the cam slot, the pin will be at its maximum
depth in the plug. Hand tighten the plug lock nut to hold the eccentric plug in position.
5. Turn the control shaft an equal amount in either direction from neutral. The switch pin should move
out of the eccentric plug an equal distance when the control shaft is turned. Turn the eccentric plug
to center the switch pin with the cam slot. Only a small amount of adjustment in either direction is
needed to center the pin.
6. While holding the eccentric plug in place, tighten the eccentric plug lock nut to 27 N•m [20 lbf•ft].
Reinstall and adjust the switch as outlined in the previous section.
The eccentric plug normally requires between 5-1/2 and 6-1/2 turns to install into the control
housing.
Eccentric plug adjustment
Eccentric plug
Switch pin
Eccentric plug
adjustment range
90°
90°
Control mounting
surface
P104 151E
Service Manual
Series 90 Pumps
Adjustments
520L0818 • Rev 0101 • August 2015
37