Gaseous Fuel System - Generac Power Systems 941-2 Service Manual

Section 2.1
GENERAL INFORMATION
TIMING:
Valve timing and ignition timing must be precisely
controlled if the engine is to operate properly and effi-
ciently. Intake and exhaust valves must open and
close in a precise timed sequence if the four strokes
are to occur. Ignition must occur at exactly the correct
piston position, just prior to the start of the power
stroke. Timing of valve opening and closing, as well
as of spark occurrence, is given in relation to the pis-
ton position and the degrees of crankshaft rotation.
Ignition Is timed to occur several degrees before top
dead center (TDC) of the piston, to allow time for the
air-fuel mixture to ignite and start to bum before the
piston reaches top dead center
There must be no leakage past the valves in their
closed position or compression will not develop.
Likewise, there must be no leakage past the piston
RECOMMENDED FUELS
GASOLINE FUEL SYSTEMS:
For models equipped with a gasoline fuel system, the
use of clean, fresh, UNLEADED, regular grade gaso-
line is recommended. Unleaded gasoline burns clean-
er, extends engine life, and promotes better starting by
reducing carbon deposits in the combustion chamber.
Leaded "Regular" grade gasoline may be used if
unleaded gasoline is not available.
The use of gasohol is NOT recommended. If it must
be used, it should not contain more than 10 percent
ethanol. When gasoline containing ethanol is used,
special care is required when preparing the unit for
storage (see "Storage Instructions"
NOTE: DO NOT USE GASOLINE CONTAINING
METHANOL.
NOTE: DO NOT MIX OIL WITH THE GASOLINE.
DANGER! GASOLINE IS EXTREMELY FLAM-
!
MABLE AND ITS VAPORS ARE EXPLOSIVE.
DO NOT PERMIT SMOKING, OPEN FLAME,
SPARKS OR ANY SOURCE OF HEAT !N THE
VICINITY WHILE HANDLING GASOLINE.
AVOID SPILLAGE OF GASOLINE ON A HOT
ENGINE. THERE MUST BE NO LEAKAGE OF
GASOLINE INTO THE RV GENERATOR COM-
PARTMENT.
Page 2.1-2
GASEOUS FUEL SYSTEMS:
Some RV generator models may be equipped with an
LP or natural gas fuel system. The use of such
gaseous fuels may result in a slight power loss as
compared to gasoline. However, that disadvantage is
usually compensated for by the many advantages
offered by such fuels. Some of these advantages are:
• A low residue content which results in minimum
carbon formation in the engine.
• Reduced sludge buildup in the engine oil.
• Reduced burning of valves as compared to gaso-
line. No "washdown" of the engine cylinder wall dur-
ing cranking and startup.
• Excellent anti-knock qualities.
• A nearly homogenous mixture in the engine cylinder.
• Fuel can be stared for long periods without break-
down.
DANGER! GASEOUS FUELS ARE HIGHLY
!
VOLATILE AND THEIR VAPORS ARE EXPLO-
SIVE. LP GAS IS HEAVIER THAN AIR AND
WILL SETTLE IN LOW AREAS. NATURAL
GAS IS LIGHTER THAN AIR AND WILL ACCU-
MULATE IN HIGH AREAS. EVEN THE SLIGHT-
EST SPARK CAN IGNITE THESE FUELS AND
CAUSE AN EXPLOSION. THE USE OF LEAK
DETECTORS IS RECOMMENDED WHEN
GASEOUS FUELS ARE USED. ALL CODES,
STANDARDS AND REGULATIONS PERTAIN-
ING TO THE INSTALLATION AND USE OF
GASEOUS FUELS MUST BE COMPLIED
WITH.
RECOMMENDED ENGINE OIL
Use a clean, high quality, detergent oil that is classi-
fied "For Service SC, SD, SE, SF or SG". Use no
special additives with the oil.
• During summer months (above 32° F. or 0° C.), use
SAE 30 oil. SAE 10W-30 oil is an acceptable sub-
stitute.
• During winter months (below 32° F. or 0° C.), use
SAE 5W-20 or 5W-30 oil.
• DO NOT USE SAE 10W-40 OIL.