Kohler K9J Service Manual page 51

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~REGULATOR
COVER
DIAPHRAGM
Figure 6-37. Typical Primary Regulator.
Two Stage Regulator
The two stage regulator used on Kohler engines is
a double diaphragm type regulator designed for
use with air-cooled engines. It combines primary
and secondary regulation in one unit. The regula-
tor fuel inlet is connected to the fuel tank. Its out-
let is connected to the carburetor. If the regulator
fails to operate properly, replace it or have it serv-
iced by an authorized gas equipment shop. Never
attempt to service
a
faulty regulator.
Vaporized fuel is admitted to the regulator at fuel
tank pressure (up to 250 psi). Because the secon-
dary valve is closed (engine not running), the
pressure on the internal side of the primary dia-
phragm builds up until the pressure overcomes the
spring action on the opposite side of the dia-
phragm. This primary diaphragm spring has suffi-
cient tension to require approximately 1 0 psi pres-
sure on the internal side of the diaphragm to
counteract the opening force due to the spring.
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When the pressure reaches this level, the valve is •
closed, preventing further pressure rise.
The secondary diaphragm acts against the secon-
dary valve spring. Its action results from vacuum
caused by the carburetor. As the vacuum begins
acting on the diaphragm, the diaphragm is moved
nearer to the center of the regulator, opening the
secondary valve until equilibrium is reached. As
more fuel is needed, vacuum from the carburetor
increases, causing the secondary valve to open
further. When fuel is flowing, pressure on the pri-
mary diaphragm is lowered slightly, permitting the
spring to open the primary valve in an attempt to
bring the pressure back to 1 0 psi. Refer to Figure
6-38.
6.25