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CRANKCASE BREATHERS
The breather element and case can be cleaned using
cleaning solvent. Make sure the small drain hole or
holes are clean and installed down to allow return of
oil back into the crankcase.
Top Mounted Breather
This type of breather is mounted in the top and rear of
the cylinder block in vertical shaft engines. The
umbrella check valve allows positive pressure to be
vented through the element and out the tube. Most
engines have the breather tube connected to the air
cleaner assembly (diag. 44).
Late production OVRM engines use the rubber boot
and breather tube as a "pop in" design. Mark or note
the location of the breather tube. Use a large flat blade
screwdriver to pry the boot up and lift the breather
assembly out. Be careful not to drop the breather body
out of the rubber boot when removing (diag. 45).
A new breather tube boot is recommended for
replacement to assure proper crankcase seal. Apply
engine oil to the breather tube boot and push the
breather in until the top shoulder of the boot contacts
the crankcase.
OHH engines use an umbrella valve type breather that
is found in the rocker arm cover. Use solvent and
compressed air to clean the area if necessary.
Individual components are serviced only by the
replacement of the complete cover.
Side Mounted Breather
This type of breather mounts over the valve
compartment and uses a reed style check valve. Clean
the internal element or reed area with solvent and
compressed air if necessary. When installing, the drain
holes must be open and be on the bottom.
On OHV13.5 - 17 engines, align the reed valve and
plate parallel to the top surface of the breather opening
in the crankcase. If the plate has a notched corner,
install the notch toward the P.T.O. side of the engine.
If the plate is marked, install the plate with the mark
facing out. Hold the reed valve and plate in this position
while tightening the screw.
45
BODY
TUBE
COVER
GASKET
47
46
49
FILTER
COVER
GASKET
DRAIN
HOLE
REED
BODY
44
PRESSURE OUT
OIL RETURN
BAFFLE
ELEMENT
TUBE
CHECK VALVE
3
5
4
1
2
UMBRELLA
BREATHER OUTLET
TO CARB
1 - Valve, Reed
2 - Plate, Limit
3 - Screw
4 - Baffle/Gasket
5 - Cover
48
