Briggs & Stratton 500 Series Maintenance Manual page 24

Engine Model: Briggs & Stratton
Excessive vibration can
indicate damage to the
blade, or blade
mounting, or that the
engine is loose
Loosening the blade
(it is a normal thread, so
turn anti-clockwise to
remove the blade)
Page 24 of 32 B&S Classic, 450 and 500 Series Selfhelp
Classic,
450 and 500 Series
Check the blade bolt is tight.
WARNING: Mark the blade before attempting
to remove it. This will enable you to replace it
the correct way up.
Check the blade mount. The mount has two
lugs one either side of the blade securing bolt.
If these have sheered then the blade can move.
If the blade mount has failed, a replacement
can be purchased through your local Mountfield
dealer.
The Blade mount is only likely to fail
because the blade has come into contact
with an obstruction of some form. The blade
mount is designed to fail in order to offer some
degree of protection to the engine crankshaft.
Check the condition of the cutter blade - if badly
worn or damaged, replace with a new one. If a
new cutter blade has been fitted, check that it
has been installed the correct way up (the wing
tips at either end should bend upward into the
mower chassis and not downward towards the
ground).
Check that all 3 bolts securing the engine are in
place and tight.
Guide 2011, Issue 1.0