Joyner Go-kart JNSZ650DS Owner's Manual page 25

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 (see Fig. 18).
c. It is advisable to replace the spark plug at least once a year to insure easy starting
and good engine performance.
SERVICE INSTRUCTIONS
F. 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 air screw gently. Back out 2-3/8 turns counter clockwise (see Fig. 19).
c. Connect the tachometer, adjust the throttle to limit the idle speed. The standard
value is (1400RPM).
d. Turn the air screw 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 step d and e until the rotate speed of engine stables.
G. 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.
Figure 19
24
Figure 18