Kohler K91 Service Manual page 28

1 /32"-1/16"
Fig ure 6-1 . Fuel Tank Cap .
( " New Look" Only)
FUEL TAN K
Engine-mounted fuel tanks o n K series engines
are constructed of steel . They are fitted with a
vented cap . The venting properties of the cap
should be checked regularly . A clogged vent can
cause pressure buildup in the tank, which could
result in fuel spraying from the filler when the cap
is loosened . It can also cause a partial vacuum in
the tank, stopping the engine.
Fuel S hutoff Valve
Some engines are equipped with a fuel shutoff
valve with a wire mesh screen . On engines without
a shutoff valve , a straight outlet fitting is used .
The wire mesh prevents relatively large particles in
the tank from reaching the carburetor. The shutoff
valve permits work on the fuel system without the
need for draining the tank.
FUEL FILTER
Some engines covered by this manual may be
equipped with a see-through in line fuel filter.
When the i nterior of the filter appears to be dirty,
it should be replaced .
FUEL PUMP
All K series engines except the K9 1 have provi­
sions for mounting a mechanically operated fuel
pump. If no fuel pump is mounted on these en­
gines , a cover is placed over the pump mounting
pad on the crankcase.
Older fuel pumps have a metal body . Later mod­
els have a body made of plastic. The plastic body
better insulates the fuel from t he hot engine , mini­
mizing the chance of vapor lock.
6 . 2
Cui Off
Operation
The mechanical fuel pump is operated by a lever
that rides on the engine camshaft . The lever
transmits a pumping action to the flexible d ia­
phragm i nside the pump body . The pumping ac­
tion draws fuel in through the inlet check valve on
the downward stroke of the diaphragm . On the
upward stroke , the fuel is forced out through the
outlet check valve . Refer to Figure 6-2 .
�
..
. �
0 ..,
MATCH MARK
! ;
�
VALVE S P R I NG/
PUMP VALVE �
�
�
VAL V E RETA I N E R
.., @) o
�
D I APHRAGM S P R I NG
Figure 6-2. Mechanical Fuel P u m p .
Removal
1 .
Disconnect the fuel lines from the inlet and
outlet fittings of the pump.
2 . Remove the fillister head sems screws , flat
washers , fuel pump and gasket .
If required , remove the fittings from the pump
3.
body .
Repair
Plastic bodied fuel pumps are not serviceable and
must be replaced when faulty. Replacement
pumps are available in kits which include the
pump, mounting gasket and plain washers .
Installation
1 . Fittings - Apply a small amount of Permatex®
Aviation Perm A Gasket (or equivalent gasoline
resistant thread sealant) to fittings . Turn fit­
tings into pump six full t u rns;
fittings in the same direction u ntil desired di­
rection is reached .
2 . Install new gasket , fuel pum p , flat washers ,
lock washers and fillister head sems screws .
Refer to Figure 6-3.
i
/ ASS E MB L Y SC REW
P U MP CO V E R
W
�
'"
VAL V E GAS KET
C)
PUMP VAL V E
�
VA L V E S P R I N G
/
�
VAL V E PLAT E S C REW
D I AP H RAGM
/
e
�
MOU NT! NG GAS KET
�
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