Gas carburation, Lp gas conversion kit – Generac 86640 User Manual
Page 67
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As the throttle is opened wider, air flow increases through
the carburetor venturi and the vacuum at the venturi throat
Increases proportionally. Diaphragm movement increases,
the regulator metering valve opens further, and gas flow to
the carburetor increases.
The following facts apply to venturi type gas carburetion
systems:
n The regulator must be properly adjusted so that it will
stop the flow of gas when the engine is not running.
D The slightest vacuum should lift the regulator metering
valve off its seat and allow gas flow to the engine.
D If diaphragm spring force is excessive, too much vacuum
will be needed to open the regulator metering valve. This
will result in a flat spot or sluggish progression off idle.
Lean mixtures and power loss at full loao may also result.
D If diaphragm spring force is too weak, fuel leakage after
shutdown may result. Hard starting and the danger of fire
exist.
DANGER:
GASEOUS
FUEL
REGULATORS
MUST
BE PROPERLY ADJUSTED AND TESTED AT THE
TIME
OF
INSTALLATION,
TO
PREVENT
GAS
LEAKAGE AND POSSIBLE FIRE OR EXPLOSION.
INSTALLATION,
ADJUSTMENT
AND
TESTING
SHOULD
BE
ACCOMPLISHED
ONLY
BY
QUALI
FIED
GAS
SERVICE
TECHNICIANS.
THE
GAS
FUEL
SYSTEM
MUST
COMPLY
WITH
ANSI
119.2/NFPA
501C,
CHAPTER
2,
“FUEL
SYSTEMS
AND
EQUIPMENT".
FOLLOWING
INSTALLATION
THE SYSTEM MUST BE PROPERLY PURGED AND
LEAK TESTED. NO LEAKAGE IS PERMISSIBLE.
Gas Carburation
See Figure 5. During the engine Intake stroke, air is
drawn into the engine. This air flows through a venturi in the
carburetor and creates a vacuum at the venturi throat. The
amount of vacuum created is proportional to the amount of
air flow. That is, the greater the air flow through the venturi,
the greater the amount of vacuum.
The vacuum created at the carburetor venturi throat acts
on a diaphragm in the vaporizer-regulator (liquid withdrawal
system) or pressure reducer valve (vapor withdrawal), to pull
the diaphragm toward the source of vacuum. Diaphragm
movement opens a metering valve and allows gas to flow to
the carburetor.
LP Gas Conversion Kit
An LP gas conversion kit is available for installation on
NP and IM generators with 1.2 liter gas engine. Installation of
thé proper conversion kit will allow LP gas to be used as a
fuel. The Model 9251 kit is a vapor withdrawal type; Model
9052 is a liquid withdrawal type. The kits do not include fuel
supply tanks, nor do they include fittings, lines, etc., required
to store the fuel and deliver the fuel to the fuel lockoff solenoid.
Instructions are included with the kit. To order instructions
only, specify manual Part No. 78360.
A primary regulator Is required for vapor withdrawal
systems. That regulator is not included in the kit.
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