272144 Vanguard Twin Cylinder OHV BRIGGS & STRATTON.pdf

GENERAL INFORMATION
Briggs & Stratton Vanguard OHV V-Twins use a
full pressure lubrication system with an oil filter. The
gear driven oil pump (1) draws oil from a screened
oil pickup (2) in the sump and pumps the oil through
the oil filter (3). The lubrication systems shown are:
Horizontal Crankshaft Engines, Fig. 1.
Crankcase Breather Identification
Vanguard engines utilize a breather valve to
control and maintain a vacuum in the crankcase.
The breather vents crankcase vapors through the air
cleaner.
Models 290000 – 351000
The breather is located on the valley between the
cylinders.
Two styles of breathers are used, Fig. 3. The current
style breather (left) uses a reed valve (1) to maintain
crankcase vacuum. Early style breathers (right)
contain a fiber disc type valve (2).
NOTE: The early breather mounting screw (3) used
a washer (4) and O-rings that are not used
on the current screw (5). The screws and
breathers are NOT interchangeable.
Fig. 1
Vertical Crankshaft Engines, Fig. 2.
ÓÓÓ
ÓÓÓ
ÓÓ
Ó
Fig. 3
ÓÓ
Ó
ÓÓ
ÓÓÓ
Fig. 2
Filtered oil flows through oil galleries in the sump and
is distributed to the main bearings, connecting rod
bearings and camshaft bearings. Engine oil
pressure will vary with oil viscosity, ambient air
temperature differences, operating temperatures
and engine load. Follow the oil recommendations in
Section 1.
A pressure relief valve limits the maximum oil
pressure in the system.
An optional oil pressure switch is available. The
switch may be used to activate a warning device if
oil pressure drops below approximately 5 psi (0.3
Bar). The warning device and wiring is supplied by
the OEM.
Models 380000, 540000, 610000
The breather is located in the valve cover of the
number 2 cylinder, Fig. 4. The breather uses a reed
valve to maintain crankcase vacuum. The reed valve
is replaceable.
Fig. 4
144