Onan CCK Service Manual

LPG VAPORIZER
The vaporizer-regulator consists of a high pressure
regulator and a vaporizer in a single unit (Figure 24).
Regulator portion of the vaporizer-regulator reduces
LPG tank pressure to a uniform outlet pressure of 7
psi (48.3 kPa). The vaporizer section installed in the
path of the engine cooling air system furnishes the
heat required to offset the cooling effect produced as
the LPG fuel is expanded and becomes gas.
The vaporizer reduces high pressure liquid fuel to low-
pressure gaseous fuef. Liquid fuel is admitted into the
Inlet part and passes through the fuel inlet orifice.
With the engine running, the pressure to the right of
the valve seat and retainer drops to open the valve, a
mixture of partially vaporized fuel enters the center
tube (first stage cold chamber) of the vaporizer. The
droplets of fuel are sprayed out of the end plug holes
Into the staggered portions of the cast heat ex¬
changer. The swirling action of the fuel ensures
complete vaporization. Dry gas leaves the exchanger
through the outlet port of 3 psi (20.7 kPa).
Vaporizer Adjustments: Adjust the vaporizer to a
working pressure of 7 psi whenever the pressure
adjusting screw is moved or the unit is overhauled.
1. Place the vaporizer in a vise or other suitable
clamp. Attach an air hose from an air supply of
approximately 75 psi (517.5 kPa) to the inlet,
Figure 25.
2. Attach a pressu re gauge capable of reading over 7
psi (48.3 kPa) to the outlet
3. Back off the adjusting screw until only one ortwo
threads are engaged. Apply air pressure to the
unit.
4. Turn the pressure adjusting screw in slowly until a
reading of 7 psi shows on the gauge.
To obtain an accurate gauge reading, it may be necessary to
unscrew the gauge partially to bleed off some of the air. Then
retighten the gauge and readjust for 7 psi (48.3 kPa). If the
pressure reading remains steady, the valve is not leaking. If the
pressure reading increases siowiy, it indicates a leaking valve.
Check the components of the vaporizer tor correct assembly
procedures. Replace defective parts.
5. Tighten the lock nut on the pressure adjusting
screw. Turn off the air pressure and remove the
gauge and air line.
FIGURE 25. VAPORIZER ADJUSTMENT
outlet port
PRESSURE
ADJUSTING
SCREW
INLET PORT
PARTIALLY VAPORIZED
^ gas
FIGURE 24. LPG VAPORIZER
31

Onan CCK Specifications

General

Cylinders	2
Ignition System	Battery ignition
Fuel Type	Gasoline
Cooling System	Air-cooled
Fuel System	Carburetor
Starter	Electric
Governor	Mechanical
Max RPM	1800 RPM
Engine Type	4-cycle
Bore and Stroke	3.25 x 3.625 inches (82.55 x 92.08 mm)