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Grain quality
Foreign material in clean grain
Possible Cause
Correction
Engine not up to correct speed.
Adjust engine high idle to proper
speed.
Separator drive belt, fan drive belt, or
cleaning shoe drive belt slipping.
Inspect drives, replace any damaged
belts and adjust idlers as required.
Missing or plugged fan inlet screen.
Clean or reinstall fan inlet screen.
Uneven feed to cylinder.
Refer to section on
UNEVEN OR BUNCHED
FEEDING (PG. 16).
Insufficient material entering cylinder.
Increase ground speed for more intake
of material.
Incorrect chaffer for crop being
harvested.
Round end, shallow tooth 1.125” (28.6
mm) spacing - generally used in corn
but has also been found to provide
desired cleaning in some crops such
as soybeans and high moisture cereal
grains where more air volume is
desired.
Square end, deep tooth 1.625” (41.3
mm) spacing - generally used in high
moisture corn to remove pieces of cob
from the tank sample.
Insufficient air blast from cleaning fan.
Increase fan choke setting.
Sieve opening too wide.
Consider increasing air, then decrease
sieve opening in 0.06” (1.6 mm)
increments.
Uneven opening of sieve or chaffer
louvers.
Straighten louvers or replace sieve or
chaffer.
Chaffer opening too wide.
Consider increasing air, then decrease
sieve opening in 0.06” (1.6 mm)
increments.
Finishing sieve required for crop and
crop conditions.
A number of finishing sieves are
available and can be used to provide
best clean in crops such as soybeans
and small or light seeds.
Excessive tailings allowing uneven
distribution of material on the cleaning
shoe.
Refer to
EXCESSIVE TAILINGS (PG. 23)
condition section.
Cleaning shoe overloaded due to over
threshing.
Refer to remedies listed under
MATERIAL LODGING OUTSIDE OF CAGE (PG.
20).
Excessive cob breakage from cage.
Optimize concave setting and cylinder
speeds.
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