National Mower 68 DL - Manual (Page 23)

NATIONAL 68 SR & DL TRIPLEX ®
23
68OM-06/03
ADJUSTING DRIVE BELT TENSION
A belt adjusted for proper tension can be deflected slightly
at a point midway between the pulleys. An over-tight belt
will cause excessive bearing wear and an under-tight belt
allows slipping, causing excessive belt wear.
IMPORTANT: Never allow oil to get on the belt which
could cause slipping.
MAIN DRIVE BELT TENSION (Main Countershaft to
Rear Drive)
Belt tension is increased by loosening the four bolts
holding the Upper Countershaft Housing (A) and sliding
the housing forward in the slotted frame holes.
NOTE - It will be necessary to remove belt guards to reach
the adjustment bolts. Also, if this belt is adjusted, it will be
necessary to readjust the engine belt. Replace all belt
guards before using the mower.
ENGINE DRIVE BELT TENSION (Engine to Main
Countershaft) (No photo)
Belt tension is increased by loosening the four engine
mounting bolts and sliding the engine forward in the
slotted frame holes. Test for the proper tension as detailed
in the section "Wing Cutting Unit Drive Belt Tension".
When tension is correct, tighten all the bolts securely.
WING CUTTING UNIT DRIVE BELT TENSION
Adjust tension by loosening set screw (B) in the wing
mower pull arm, sliding the Cutting Unit rearward and
retightening set screw.
REAR CUTTING UNIT DRIVE BELT TENSION
Spacers (A) are provided on the rear mower Pull Rod (B)
to adjust the belt tension. Remove Pin (C) from the end of
the pull rod and slip out the pull rod from the Pivot Tube
(D). Move as many spacers as necessary to the location
indicated and reassemble.
FRONT
OF
MACHINE