RHINO FX17 Operator's Manual page 152

MAINTENANCE
The actual speed at which the harmonic will occur will vary with each mower and each installation. To avoid
this harmonic vibration when operating the mower, it may be necessary to adjust the engine speed of the
tractor up or down.
Some units have a harmonic which occurs below the nominal operating speed. On these units, it will be noticed
that there is always a little vibration at a particular RPM as the mower is being sped up to operating speed. This
occurs as the shaft passes through its normal harmonic vibration point. As long as the mower is opened at the
proper speed, then harmonic vibration will not be an issue.
FX17/FX21 02/11 Maintenance Section 5-12
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