Section 5. Fuel System And Governor - Kohler LH630-775 Service Manual

Fuel System and Governor
Description
The Aegis horizontal twins use two different types of
fuel systems; carbureted or electronic fuel injection
(EFI).
This section covers the standard carbureted fuel
systems. The EFI systems are covered in subsection 5B.
The governor system, covered at the end of this
section, is the same for both fuel systems.
WARNING: Explosive Fuel!
Gasoline is extremely flammable and its vapors can explode
if ignited. Store gasoline only in approved containers, in
well ventilated, unoccupied buildings, away from sparks or
flames. Do not fill the fuel tank while the engine is hot or
running, since spilled fuel could ignite if it comes in contact
with hot parts or sparks from ignition. Do not start the
engine near spilled fuel. Never use gasoline as a cleaning
agent.
Fuel System Components
The typical carbureted fuel system and related
components include the following:
• Fuel Tank
• In-line Fuel Filter
• Fuel Pump
• Carburetor
• Fuel Lines
Operation
The fuel from the tank is moved through the in-line
filter and fuel lines by the fuel pump. On engines not
equipped with a fuel pump, the fuel tank outlet is
located above the carburetor inlet, allowing gravity to
feed fuel to the carburetor.
Fuel then enters the carburetor float bowl and is
moved into the carburetor body. There, the fuel is
mixed with air. This fuel-air mixture is then burned in
the engine combustion chamber.
Section 5
Fuel Recommendations
General Recommendations
Purchase gasoline in small quantities and store in
clean, approved containers. A container with a
capacity of 2 gallons or less with a pouring spout is
recommended. Such a container is easier to handle
and helps eliminate spillage during refueling.
• Do not use gasoline left over from the previous
season, to minimize gum deposits in your fuel
system and to ensure easy starting.
• Do not add oil to the gasoline.
• Do not overfill the fuel tank. Leave room for the
fuel to expand.
Fuel Type
For best results, use only clean, fresh, unleaded
gasoline with a pump sticker octane rating of 87 or
higher. In countries using the Research fuel rating
method, it should be 90 octane minimum.
Unleaded gasoline is recommended as it leaves less
combustion chamber deposits and reduces harmful
exhaust emissions. Leaded gasoline is not
recommended and must not be used on EFI engines,
or on other models where exhaust emissions are
regulated.
Gasoline/Alcohol blends
Gasohol (up to 10% ethyl alcohol, 90% unleaded
gasoline by volume) is approved as a fuel for Kohler
engines. Other gasoline/alcohol blends are not
approved.
Gasoline/Ether blends
Methyl Tertiary Butyl Ether (MTBE) and unleaded
gasoline blends (up to a maximum of 15% MTBE by
volume) are approved as a fuel for Kohler engines.
Other gasoline/ether blends are not approved.
Fuel System and Governor
Section 5
5
5.1