Kohler LH630-775 Service Manual page 81

Section 6
Lubrication System
To install the switch, follow these steps:
1. Apply pipe sealant with Teflon
59241 or equivalent) to the threads of the switch.
2. Install the switch into the tapped hole in the
breather cover. See Figure 6-5.
3. Torque the switch to 4.5 N·m (40 in. lb.).
Testing
Compressed air, a pressure regulator, pressure gauge
and a continuity tester are required to test the switch.
1. Connect the continuity tester to the blade
terminal and the metal case of the switch. With 0
psi pressure applied to the switch, the tester
should indicate continuity (switch closed).
2. Gradually increase the pressure to the switch. As
pressure increases through the range of 3.0/5.0
psi, the tester should indicate a change to no
continuity (switch open). The switch should
remain open as the pressure is increased to
90 psi maximum.
3. Gradually decrease the pressure through the
range of 3.0/5.0 psi. The tester should indicate a
change to continuity (switch closed) down to
0 psi.
4. Replace the switch if it does not operate as
specified.
Crankcase Breather System
The crankcase breather system is a necessary
complement to the lubrication system. To help
prevent the engine oil from weeping out past shafts,
seals, and gaskets during operation, it is desirable to
have a low vacuum inside the crankcase. A typical
crankcase breather system incorporates a simple one-
way valve to provide the desired vacuum.
6.4
Breather Design and Function
The breather system on these engines is designed to
® ®
(Loctite No.
control and maintain the vacuum in the engine
crankcase. When the pistons move downward, a
controlled amount of crankcase air is pushed past the
reed, which in turn closes when the pistons travel
upward. The hole for the breather (reed) is positioned
high in the crankcase, so that most of the oil mist has
already been purged from the air before it enters the
breather chamber. Remaining oil is separated
through a baffle and filter, as the air moves through
the chamber. A hose connects the breather outlet to an
adapter on top of the carburetor, where the vented
breather air is mixed proportionately with the
incoming combustion air on its way to the
combustion chamber. A drain hole at the bottom of
the chamber returns the separated oil to the
crankcase.
Figure 6-6. Reed/Breather Assembly in Crankcase.
Figure 6-7. Breather Cover.