Great Plains 3N-4025P Operator Manual - Manual (Page 82)

78 3N-40P Table of Contents Index Great Plains Manufacturing, Inc.
196-538M Table of Contents Index 2014-01-29
Frame-Mounted Coulter Force
Coulter springs are set to 400 pounds (181 kg). In
normal operation at target running depth, the spring is at
full extension. It compresses briefly as obstructions are
encountered.
• In heavy no-till conditions, you may observe the
springs in compression most of the time. This means
that the blades are not reaching the desired coulter
depth. If adequate drill weight is available, you can
increase the spring down-force to compensate.
• In light but rocky conditions, the factory spring setting
may be higher than needed. You can extend blade life
by reducing the force at which the blades ride up over
obstructions.
To adjust the coulter spring:
Refer to Figure 96
1.
Raise the drill and install transport locks. See “Lift /
Lower” on page 25.
2. Determine the new spring length desired. See the
table at right.
3. Measure the current length of the spring(s) to be
changed. If already shorter than
9
3 ⁄
4
inches (24.8 cm), or longer than
10
1 ⁄
4
inches (26 cm), do not further adjust them.
4. Loosen the jam nut .
5. Rotate the adjuster nut until the spring is at the
new length. Tighten the jam nut.
Note: If all springs are continuously in compression, the
coulters can lift the wing frames off the ground (at
the wheels), resulting in uneven coulter depth
and/or uneven seed depth. If high forces are
required, frame weights are probably required.
Do use spring lengths shorter than 9.75 in (24.8 cm). It may
contribute to premature parts failure which will not be covered
by warranty.
Figure 96
Frame-Mounted Coulter Spring
27139
Spring Length Force at Blade
10.25 inch (26.0 cm) 300 pounds (136 kg)
10.00 inch (25.4 cm) 400 pounds (181 kg)
9.75 inch (24.8 cm) 525 pounds (238 kg)
1
1
2
3
1
2
3