Service Manual

4 - 4 Service Dealer’s Guide to Great Quality of Cut
Checking and Adjusting the Blade Level
If you don't have the measuring tool, use a piece
of wood just short enough to fit under the mower
housing. Wrap one end with tape. Place the
untaped end on the floor and the tape against the
cutting edge of the blade (Figure 17). Make a
mark in the tape with the blade. Measure from the
end that was on the floor to the mark you made in
the tape and record the measurement on your
sketch. Cover the marked tape with a fresh piece
of tape. Repeat this process for each
measurement, adding another layer of tape after
each measurement so you have only one mark
each time you measure.
Figure 17
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6. When the measurements are complete, proceed
to the subsections in these instructions that cover
the blade tracking and blade leveling procedures
for the mower on which you are working.
Checking and Adjusting
Blade Tracking
Walk Behind Mowers
Blade tracking can generally be checked visually. Use
one blade tip turning it one rotation. It should stay close
to the same level all the way around, a minimum of
approximately 1/8 inch (3.1mm) above the bottom
edge (Figure 18) of the mower housing. (Housings with
cut-outs are more difficult to check. Verify all other
measurements when checking these mowers.) If there
is a large difference in the measurement from one area
to another, the mower housing may be bent at the point
where the engine or blade spindle mounts. You can
correct for this by placing shim washers between the
engine or spindle and the housing. Check for level after
installing shims.
Figure 18
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Riding Mowers
For instructions on checking and adjusting the blade
tracking on a riding mower, see the subsection in these
instructions that covers the mower on which you are
working.
Adjusting Blade Level
Walk Behind Mowers
Specifications and Tolerances
On walk behind mowers the blade should be level
side-to-side within 1/8 inch (3.1mm).
The mower is designed with a 1-degree downward
blade pitch when the tips of the blade are at the
12 o'clock and 6 o'clock positions from the operator's
position. The difference between the measurement at
the front and the rear will vary with the blade length.
See the following table for common measurements.
Note: Tolerances in everything including wheels and
pivot arms make the blade pitch specification
approximate. Although the blade should not be level
front to rear, it should not be tilted excessively. If the
front-to-rear difference is within 1/8 inch (3.1mm) of the
specification, the pitch is acceptable.