Joyner Dirt Devil SZ250DS 2006 Owner's Manual And Parts Manual page 22

D. Spark Plug
a. Remove the spark plug and inspect it each
time you change the oil. (Use a spark plug
wrench) The electrodes should be kept clean and
free of carbon. The presence of carbon or excess
oil will greatly reduce proper engine performance.
If possible, check the spark plug gap (area
between electrodes) using a wire feeler gauge.
This specification is 0.025"~0.030".
b. Before installing spark plug coat threads
lightly with graphite grease if possible, to ensure
easy removal next time the spark plug needs
inspection.
c. It is advisable to replace the spark plug at least once a year to insure easy starting and
good engine performance.
E. Carburetor Adjustment
Never make unnecessary adjustments. The factory recommended settings are
correct for most applications. It's not necessary to disassemble the screw unless the
carburetor needs to be replaced. Prepare a 50r/w tachometer before adjustment.
a. Warm up the engine (5~10min)
b. Tighten the airscrew gentle. Back out 2-3/8 turns counter clockwise.
c. Connect the tachometer; adjust the throttle to limit the idle speed. The standard value
is (1400RPM).
d. Turn the airscrew counter slowly and observe the RPM of the engine, stop adjusting
as the RPM reaches the top speed.
e. Adjust the screw and adjust the idle speed to an ideal value.
f. Repeat steps d) and e) until the rotate speed of engine stables.
F. Cleaning Instructions
Keep your kart clean. With a clean rag, wipe off and dirt and oil from around
controls. Wipe off any spilled fuel and oil. Keep the engine clean of foreign object and be
sure to check that air intake fan is free of debris for proper cooling.
G. Kart Lubrication
Lubricate vehicle every 90 days of use, Apply several drops of oil in specific
points.
H. Chain Lubrication
To increase chain life, it should be lubricated with a spray on type chain lubricant.
Figure 8