General Information And Design; Cooling; Carburetor; Horsepower - Wisconsin vg4d Repair Manual

GENERAL INFORMATION and DESIGN
Wisconsin engines are of the four cycle type, in which each
of the four operations of intake, compression, expansion
andexhaustrequiresacompletestroke. This gives onepower
stroke per cylinder for each two revolutions of the crankshaft.
COOLING
Cooling is accomplished by a flow of air, circulated
over the cylinders and heads of the engine, by a
combination fan-flywheel encased in a sheet metal
shroud. The air is divided and directed by ducts and
baffle plates to insure uniform cooling of all parts.
Never operate an engine with any part of the
shrouding removed - this will retard air cooling.
Keep the cylinder and head fins free from dirt and
chaff. Improper circulation of cooling air will
cause engine to overheat.
CARBURETOR
The proper combustible mixture of gasoline and air
is furnished by a balanced carburetor, giving correct
fuel to air ratios for all speeds and loads.
IGNITION SYSTEM
The spark for ignition of the fuel mixture is furnished
by a high tension magneto driven off the ~:iming gears
at crankshaft speed. The magneto distributor rotor
turns at half-engine speed. The magneto is fitted with
an impulse coupling, which makes possible a power-
ful spark for easy starting. Also, the impulse coupling
automatically retards the spark for starting, thus elim-
inating possible kick back from engine while cranking.
Battery ignition (12 volt) distributor is furnished
place of magneto on engines equipped with flywheel
alternator or belt driven generator. See Page 13.
LUBRICATION SYSTEM (Fig. 3)
A gear type pump supplies oil to four nozzles which
direct oil streams against fins on the connecting rod
caps. Part of the oil enters the rod bearing through
holes in the rods, and the balance of the oil forms a
spray of mist which lubricates the cylinder wails and
other internal parts of the engine. An external oil line
from the oil header tube in the crankcase lubricates
the governor and gear train.
GOVERNOR
A governor of the centrifugal flyweight type maintains
the engine speed by varying the throttle opening to
suit the load imposed upon the engine. These engines
are equipped with either a fixed speed governor, a
variable speed control to regulate the governed speed
of the engine, or an idle control.
ROTATION
The rotation of the crankshaft is clockwise when
viewing the flywheel or cranking end of the engine.
This gives counter-clockwise rotation ~hen viewing
the power take-off end of the crankshaft. The flywheel
end of the engine is designated the front end, and the
power take-off end, the rear end of the engine.
R.P.M. VG4D HORSEPOWER
1400
25
1600
29
1800 32
2000
34
2200
36
2400
37
HORSEPOWER
Horsepower specified in the accompanying chart is for
an atmospheric temperature of 60 o Fahrenheit at sea
level and at a Barometric pressure of 29.92 inches of
mercury.
For each inch lower the Barometric pressure drops,
there will be a loss in horsepower of
For each 10° temperature rise there will be a reduc-
tion in horsepower of 1%.
For each 1000 ft. altitude above sea level there will
be a reduction in horsepower of 3~/~%.
The friction in new engines cannot be reduced to the
ultimate minimum during the regular block test, but
engines are guaranteed to develop at least 85 per cent
of maximum power when shipped from the factory. The
power will increase as friction is reduced during the
first few days of operation. The engine will develop
at least 95% of maximum horsepower when friction is
reduced to a minimum.
For continuous operation, allow 20% of horsepower
shown as a safety factor.
STARTING and OPERATING INSTRUCTIONS
Engines that are enclosed in a sheet metal house, as
shown in bottom view of Fig. 1. are called power
units. Others are furnished without a house, as shown
in top view of Fig. ], and are called open engines.
On engines with a house, the side doors must
always be removed when operating.
This is necessary for circulating sufficient air for
cooling the engine.
LUBRICATION
Before starting a new engine, fill the oil base with
good *gasoline engine" oil, as specified in the *Grade
of Oil" chart. Fill through the breather tube shown in
Fig. 3, with 5 quarts of oil.
For run-in of new engines, use same oil
as recom-
mended in Grade of Oil Chart.
After the engine has been run for a short time, the oil
lines and oil filter will have been filled with oil. Shut
off the engine and check the oil level by means of
dip stick (oil gauge saber). If necessary, add enough
oil to bring level up to the full mark. The standard dip