Reassembly
Reassembly is for the most part, the reverse of disassembly.
The following special instructions
should be noted:
Main Fuel Valve: Place new O
-
ring on inlet orifice and turn orifice part way into casting. After
installing fuel valve lever in slot in valve stem, install axle and retainer. For
K662,
place gauge
(#C161-194) on machined surface of casting and against nylon roller.
Turn inlet orifice in or out
(with screwdriver
1/2" blade) until fuel lever is positioned in 3rd notch (above casting face) on
gauge.
If this gauge is not available, set at
.090"
above machined surface of casting for
K662,
or
at
.060" for K482, K532 models.
Secure orifice with 8
-
32 Allen setscrew.
~e~ulator Diaphragm Assembly: Install three aligning studs (from tool #C166-52) in casting.
-1 components so openings correspond
-
-
install in following order:
1.
Gasket.
2. Inner diaphragm (spacer cup out).
3.
Diaphragm spacer (recessed side out).
4.
Outer diaphragm (diaphragm plate in).
5.
Diaphragm cover.
Install three cover screws then remove aligning studs and replace
with remaining cover screws.
Idle Diaphragm:
Use new valve disc. After reinstalling housing and lever, position diaphragm
lcup side next to lever) and cover then secure with cover screws and lock washers.
After carburetor is completely reassembled, make preliminary adjustments as shown in Figure
12-6.
Carefully check carburetor and connections for leaks after reinstalling on engine.
GAS REGULATORS
Model F1
(F)
and KN secondary regulators are used. While they differ in appearance, they are
single diaphragm type regulators which function to control the amount of fuel entering an engine under
varying speed and load conditions. Vacuum created within the engine is communicated to one side of
the diaphragm while the other side is subject to atmospheric pressure. Movement of the diaphragm
caused by this difference in pressure is transmitted through linkage to the fuel valve which opens to
admit fuel to the carburetor.
The higher the pressure differential, the greater the volume of fuel.
The secondary regulator receives fuel from the primary regulator at a pressure of 4 to
7
ounces
per square inch
(7-12" water column) and reduces this to about 3 ounces when the engine is at idle.
When the engine is stopped, the fuel valve in the secondary regulator should close to prevent fuel from
entering the carburetor.
A manual or electrically operated fuel shut
-
off valve is often used in the
system to provide a more positive means of turning off the fuel.
TROUBLE ANALYSIS
CONDITION
ENGINE FAILS TO START
ENGINE IDLES POORLY
ENGINE OPERATES POORLY UNDER LOAD
POSSIBLE FAULT
1.
Main diaphragm broken or linkage
binding--
no fuel.
2.
Fuel valve stuck open
--
too much fuel.
-
1.
Idle line connections leaking or plugged.
2.
Diaphragm stiff or ruptured.
3.
Balance line plugged.
1. Excessive pressure
--
regulator discharges
in surges.
2.
Balance line improper size or restricted.
3.
Dirt in regulator causing sticking or sluggish
operation of fuel valve.
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