Reel Backlapping - Jacobsen LF 4675 Maintenance Manual

4 MAINTENANCE

4.20 REEL BACKLAPPING ______________________________________________________

WARNING
To prevent severe injury, keep hands, feet, and clothing
away from rotating reels.
Carbon monoxide in the exhaust fumes can be fatal
when inhaled. Never operate the engine without proper
ventilation
Check the reel and bedknife to determine if backlapping or
grinding will restore the cutting edge.
If wear or damage is beyond the point where the cutting
edges can be corrected by the lapping process, they must
be reground.
To backlap:
1. Lower the reels to the ground, disengage all drives,
engage parking brake, and stop engine.
2. Loosen locknut (D) at valve stem.
3. Start the engine and set throttle to low idle speed.
4. Open hood and place back-lap switch (B) to ON.
Reels will begin rotating immediately.
5. Both the front and rear reel valves contain an
adjustable valve (C) to control the speed of the reels.
The front valve controls the front three reels. The back
valve controls the two rear reels. Turn valve counter-
clockwise to reduce reel speed. Repeat for both valves.
6. After the desired speed is set, turn backlap switch (B)
to OFF and stop engine. Tighten nut (D) to lock
adjustment in place. Start engine and set backlap
switch to ON to begin backlapping.
7. Apply lapping compound, with a long handled brush,
along the entire length of the reel.
8. When the blades have been evenly honed, carefully,
and thoroughly wash off the remaining mixture.
9. Repeat the entire process on the other reels.
10. After backlapping set backlap switch (B) to OFF.
Important: The speed control valves limit reverse speed
only. Once the desired backlapping speed has been set the
valves can remain in this position for normal mowing. If full
reverse speed is needed, for instance during operation of
vertical mowers, the valve can be fully closed (turn
clockwise).
24
C
REAR REEL VALVE SHOWN,
REPEAT FOR FRONT VALVE
B
LF021
Figure 4E
D
LF022
Figure 4F