Textron Jacobsen HR-5111 Technical/Repair Manual page 365

Definition of Terms
The following terms are used to describe various cut
appearance symptoms.
Washboarding
NOTE: Arrow indicates direction of travel.
Probable Cause
Mowing (ground) speed is too fast.
Improper tire pressure.
Mowing in the same direction.
Incorrect weight transfer adjustment, cutting units have too much
or too little weight on them.
Insufficient engine speed, not set to specification.
Hydraulic system and/or rotary drive motor performance is
reduced.
4203780 First Edition
Washboarding is a cyclical pattern of varying cutting
heights, resulting in a wave-like cut appearance. In most
cases, the wave tip-to-tip distance is approximately
6—8 in. (15—20 cm). Color variation (light-to-dark) may
also be noticed.
This condition is usually caused by a rocking motion in
the cutting unit(s). This condition is found mostly on
mowers with multiple (suspended) cutting units.
Washboarding may also be caused by variations in the
turf.
TN0159
Reduce mowing (ground) speed.
Set front machine tires at 20 psi, rear machine tires at 10 psi, and
caster tires at 23 psi.
Change mowing direction regularly.
Use weight transfer knob to transfer weight on or off cutting units.
(See "Weight Transfer Adjustment" on page 5-32.)
Check/adjust engine speed. (Refer to "Safety, Operation, and
Maintenance Manual.")
Check hydraulic system performance (pump output, motor
operation, valve operation, relief valve settings, etc.). (See
"Instrument Test Procedure" on page 6-27.)
CUTTING UNITS
Remedy
8
8-9