Compression; Compression Test - Briggs & Stratton Vanguard 05000 Manual

Dry plug symptoms:
• Leaking carburetor mounting gaskets
• Gummy or dir ty carburetor, fuel line or
tank
• Float needle valve stuck shut
• Inoperative fuel pump
• Inoperative anti–afterfire solenoid
To determine if fuel is getting to the combustion
chamber through the carburetor, remove the
spark plug and pour a small quantity of gasoline
through the spark plug hole. Replace the spark
plug.
If the engine fires a few times and then stops:
• Focus your attention on dry plug
symptoms.
If the engine does not fire:
• Replace the spark plug.

COMPRESSION

Check the sealing capability of compression
components by using cylinder leakdown tester
. The leakdown test will identify which
Tool# 19545
components may be at fault.
A regulated amount of compressed air is used to
pressurize the combustion chamber with the
piston at Top Dead Center (TDC) on the
compression stroke. By listening for air leaks, it
is possible to isolate a specific component or
components causing a problem. An engine in
good condition will display a reading in the green
area on the outlet gauge with a minimum of
audible leakage. A reading in the yellow or red
area along with high audible leakage noise,
indicates a problem with the compression
components.
A small amount of air leakage is normal in all
engines, including new engines, providing that
the outlet gauge remains in the green area.
However, if a single component is displaying
more audible leakage, look to that component for
a potential problem.
For example:
Frequently, a slight air leak at the head gasket
may not register on the gauge. Obviously the
head gasket would require replacement, as any
leak at the head gasket would have an adverse
affect on engine performance.

Compression Test

1. Run engine for 5 minutes allowing engine
to reach operating temperature.
NOTE
: If engine is cold or cannot be started, air
flow may be higher (gauge readi ngs lower)
because compression components are not at
normal operating temperatures.
2. Remove spark plugs from engine.
Disconnect air cleaner tube and cylinder
breather tube at carburetor intake elbow.
3. Rotate crankshaft in direction of operation
until piston for cylinder being tested is at
top dead center of the compression
stroke.
WARNING
Injury may occur if the crankshaft is
allowed to rot ate or the engine is not
securely fastened to a stand or the
application. The air pressure can create a
substantial rotational force if the cranks haft
is not locked with the piston at top dead
center.
4. Assemble the clamping tool (comes in kit
) to the crankshaft. Tighten screws
#19545
(A) secu rely to prevent the crankshaft
from turning.
5. Insert drive end of a 3/8" breaker bar into
slot of clamp. Hold the breaker bar to
prevent the crankshaft from turning or
install a bolt through the slot of the tool
([B] Fig. 2) into an open hole in the bolt
circle of the cylinder cover.
Fig. 2
2
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