The Model 2093A tester is equipped with a dial calibrated from 0 to 300 lbs.
pressure. A valve, located in the bottom of the check valve fitting, is provided to
release the air pressure in the gauge.
A set of adapters, Figure 1, w i t h threads to match the spark plugs of
v a r i o u s engines is provided. A flexible extension is also furnished for use in
r e s t r i c t e d p l a c e s . T h e cone adapter fitting is used for quick succession
C O M P R E S S I O N T E S T . T h e engine oil level, grade and cleanliness should be
n o t e d before making this test. W h e n removing spark plugs for a compression
t e s t , first loosen the plugs slightly and then with an air hose blow out all the
a c c u m u l a t i o n of dirt and foreign substances, which usually become pocketed
a r o u n d the spark plug. T h i s will prevent a particle of foreign matter from
dropping into the combustion chamber and becoming lodged under a valve. A valve
thus held open will cause an erroneous compression reading of the cylinder. After
the plugs are removed, it is a good plan to apply the air hose for blowing out the
combustion chambers. Observe the spark plugs as they are removed for evidence of
fouling, burning, heat range, etc.
The engine should be up to normal operating temperature before starting
t h i s test to assure normal oil and metal expnsion conditions.
C r a n k the engine with the starting motor with the ignition OFF. In case
of ignition switch-operated starting motor, ground ignition coil high-tension wire
and use the ignition switch.
When making a
compression test of an engine, the operator should take
c a r e to see that the
highest gauge reading is obtained for each cylinder with
turns of the starting motor. U s u a l l y about eight turns
t h e same number of
( w h i c h easily can be
counted) of the motor is sufficient for each cylinder.