Briggs & Stratton MB (18 HP) Lawn Mower User Manual


 
50
Maintenance Instructions REPLACING/REPAIRING
2. Rotate U-joint on shaft to align the shear pin hole
with the hole (and shear pin fragment) in the
shaft. Use a punch to drive the remaining portion
of the old shear pin out.
3. Install new shear pin and secure with cotter pin.
PTO Shear Pin
IMPORTANT: Use only Walker P/N 8067-13
shear pins for replacement to provide proper
shock protection -- these pins are hardened to
shear under a specific amount of load.
4. Reinstall the PTO shaft guard.
Before operating the deck, inspect the blade over-
load shear bolts and also check blade timing (on gear
driven decks) by moving blades through one (1)
complete revolution. Make sure blade tips pass
clear of each other. If timing is incorrect, contact your
Walker Dealer.
Mower Blades
Mower blades are removed and remounted as de-
scribed in the Sharpen Mower Blades instructions.
During the course of sharpening and inspecting
mower blades, if there are any of the following con-
ditions of wear or damage, blades should be re-
placed for reasons of safety and performance of the
machine:
An excessive amount of the flat section of the
blade has been ground away (removed) when the
blade is sharpened. Replace the blade when less
than a 3/4 in. (19 mm) flat section remains at the
blade tip.
Examine ends of the blade carefully, especially the
intersection where the flat section of the blade turns
up to form the “wing tip” (refer to Mower Blade Pro-
file For Sharpening illustration in Sharpen Mower
Blades instructions). Since sand and abrasive ma-
terial can wear metal away in this area, the blade
should be replaced when metal thickness has
worn to 1/16 in. (1.6 mm) or less.
Check the blades for straightness by marking
blade tip position inside the deck housing and then ro-
tating the opposite end of the blade to the same po-
sition and comparing. If the difference in blade tip
track is more than 1/8 in. (3 mm), the blade is bent
and should be replaced.
Inspect the blade surface, especially in formed
areas, for cracks. Replace the blade if any cracks
are found.
Reinstall the blades following procedure from Sharp-
en Mower Blades instructions. If blades are re-
placed, always use Walker original equipment
blades to ensure safety and optimum performance.
The quality and performance of replacement blades
offered by other manufacturers cannot be guar-
anteed, they could be dangerous.
Cotter Pin
U-Joint
Tube Assembly
Shear Pin
Split Spring Pin
U-Joint
Shaft Assembly
Set Screw
DANGER
When blades are operated over sandy soil,
and if blades are allowed to wear, a “slot”
may be worn into the wing tip of blade.
Eventually a piece of the blade may break
off creating a serious potential for injury or
damage.
WARNING
DO NOT try to straighten a blade that is
bent. NEVER weld a broken or cracked
blade. ALWAYS replace with a new blade
to assure safety.
CAUTION
ALWAYS use genuine factory replacement
parts. Substitute parts CAN result in prod-
uct malfunction and possible injury to the
operator.