Main Oil Pump (Engine Lubrication Circuit) - Rotax 912 Series Maintenance Manual

2.2)

Main oil pump (Engine lubrication circuit)

See Fig. 79-3
The trochoid oil pump sucks the engine oil out of the oil tank (1) via line (2). The
oil passes through the oil cooler (3) fitted on the suction side via the oil line (4)
to the oil pump rotor (5) (main oil pump), which is driven by the oil pump shaft
(6).
The pump forces the oil through the filter mat from the outside to the inside of
the oil filter (7). The oil pressure from 1.5 to 5 bar (22 to 72 p.s.i.) is controlled
by the pressure relief valve (8). The surplus oil returns to the oil pump rotor via
the channel (9).
If the filter mat in the oil filter is completely clogged up, the pressure relief valve
(10) will open and lube oil will flow unfiltered to the individual lubrication points.
Prevent this situation by all means, using lube oil and filter as specified and
carrying out punctual replacement of oil filter.
The oil will then be pumped through the oil duct (11) in the left side of the housing.
The 4 hydraulic valve tappets (12) for cylinders 2 and 4 are supplied with oil via
this channel. Oil flows to the rocker arm bearing via the hollow push-rod (13) and
the oil duct (14). The oil emerging from bore (15) lubricates the valve mechanism
and flows through the oil return line (16), into the channel (17) and back to the
crankcase.
Forced oil supply from oil duct (11) is also supplied to camshaft bearing (18)
CC23, main bearing (19) CC13, the conrod bearing (20) of cylinder 4 and the
bronze bush (21) of the backing bearing IH01 in the ignition housing.
In the crankcase sealing surface (22), the oil enters the right crankcase half. As
a result, the camshaft bearing (24) CC22, the middle main bearing (25) CC12
and the two conrod bearings (26) and (27) of cylinders 3 and 2 are lubricated
via the oil duct (23). This oil duct supplies the hydraulic valve tappets and the
valve mechanism of cylinders 1 and 3.
The forced oil supply then reaches the camshaft bearing (28) CC21, the main
bearing (29) CC11, the conrod bearing (30) of cylinder 1 and the backing bearing
(31) GB01 in the gearbox housing. The electrical connection of the oil pressure
gauge is at the oil pressure sensor (32) .
Effectivity 912/914 Series
Edition 1 / Rev. 0
BRP-Rotax
Maintenance Manual
79-00-00
page 5
May 01/2007