Troubles Causes And Remedies; Starting Difficulties; Fuel Mixture - Wisconsin VH4D Repair Manual

Fig. 17
2. Open these covers frequently and clean out all
dust and chaff. Be sure to close covers.
3. Keep this space between cylinders free of dust
and chaff.
4. Read instructions on this air cleaner regarding its
care. This is important. The entire air cleaner
should be removed from the engine at least once a
year, and washed in a cleaning fluid to clean out
dirt gathered in the back fire trap in the top part
of the air cleaner.
5. Empty pre-cleaner of accumulated dust and dirt
frequently. Do not use oil or water in pre-cleaner,
this must be kept dry.
6. Replace this oil filter cartridge every other oil
change. If operating conditions are extremely dusty
replace cartridge every oil change. Be sure that
your replacement is a Wisconsin Micro-Fine filter.
7. Do not allow shrouding to become damaged or bad-
ly dented as this will retard air flow.
Never operate engine with air shrouding re-
moved. This will retard air cooling.
Always keep all parts of the engine clean.
This will prolong engine life, and give more
satisfactory operation.
Every 4 to 8 hours, depending on dust conditions,
check air cleaner and change oil. See Page lO.
Every 8 hours check crankcase oil level, Keep filled
to full mark on oil gauge sabre, but no more. See
Fig. 3.
Every 50 hours drain crankcase and refill with fresh
oil. See Lubrication, Pages 6 and 7.
TROUBLES
CAUSES AND REI~EDIES
Three prime requisites are essential to starting and
maintaining satisfactory operation of gasoline en-
gines. They are:
1. A proper fuel mixture in the cylinder.
2. 6ood compression in the cylinder.
3. 6ood spark, properly timed, to ignite the mixture.
If all three of these conditions do not exist, the en-
gine cannot be started. There are other factors which
will contribute to hard starting; such as, too heavy a
load for the engine to turn over at a low starting
speed, a long exhaust pipe with high back pressure,
etc. These conditions may affect the starting, but do
not necessarily mean that the engine is improperly
adjusted.
As a guide to locating any difficulties which might
arise, the following causes are listed under the three
headings:
Fuel Mixture, Compression, and Ignition.
In each case, the causes of trouble are given in the
order in which they are most apt to occur. In many
cases the remedy is apparent, and in such cases no
further remedies are suggested.
STARTING DIFFICULTIES
FUEL MIXTURE
No fuel in tank or fuel shut-off valve closed.
Fuel pump diaphragm worn out, so pump does not
supply carburetor with fuel.
Carburetor not choked sufficiently, especially if en-
gine is cold. See 'Choke', Page 9.
Water, dirt, or gum in gasoline interfering with free
flow of fuel to carburetor.
Poor grade or stale gasoline that will not vaporize
sufficiently to form the proper fuel mixture.
Carburetor flooded, caused by too much choking
especially if engine is hot. See 'Choke', Page 9.
Dirt or gum holding float needle valve in carburetor
open. This condition would be indicated if fuel con-
tinues to drip from carburetor with engine standing
idle. Often tapping the float chamber of the carbu-
retor very lightly with the handle of a screw driver or
similar tool will remedy this trouble. Do not strike
carburetor with any metal tools, it may cause serious
damage. Also if the mixture in the cyhnder, due to
flooding, is too rich, starting may be accomplished by
continued cranking, with the carburetor choke open.
If, due to flooding, too much fuel should have enter-
ed the cylinder in attempting to start the engine, the
mixture will most likely be too rich to burn. In that
case, the spark plugs should be removed from the cyl-
inders and the engine then turned over .several times
with the starting crank, so the rich mixture will be
blown out through the spark plug holes. The choke on
the carburetor should of course be left open during
this procedure. The plugs should then be replaced
and starting tried again.
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