46 MAINTENANCE
NOTE: If a carburetor choke
cable is adjusted too tight, the
engine will only operate on one
cylinder at idle.
Synchronizing Piston
Valves
1. Remove the air-intake silencer
boots from the silencer to access
the intake bores.
2. Rotate the idle speed screws coun-
terclockwise until all spring ten-
sion is removed.
0727-156
3. Loosen the jam nut securing each
throttle cable swivel adapter; then
rotate each swivel adapter clock-
wise until each piston valve bot-
toms in the piston valve bore.
4. In turn on each carburetor, place a
finger lightly against the side of
the piston valve; then rotate the
carburetor swivel adapter counter-
clockwise until slight upward
movement of the valve is noted.
5. Check to make sure the valves
start to open at the exact same
moment by placing a thumb and
finger against the valves; then
lightly compress the throttle lever.
NOTE: If an individual piston
valve starts to open before
another, rotate the swivel adapter
on the valve which is lifting first
clockwise, just enough to synchro-
nize the valves. Recheck by repeat-
ing steps 2-5.
6. With the piston valves synchro-
nized, tighten the swivel adapter
jam nuts securely. Slide the rubber
throttle cable caps down over the
swivel adapters.
NOTE: There must be free-play
in the throttle lever on all models.
7. In turn on each carburetor, place a
finger against the piston valve.
Rotate the idle speed screw clock-
wise until it contacts the valve.
8. Compress the throttle lever to the
full-open position; then rotate each
idle speed screw clockwise 2 com-
plete turns. Release the throttle lever.
NOTE: There must be 0.75-1.5
mm (0.030-0.060 in.) free-play
between the throttle lever and the
control housing.
9. At this point, there must be 0.75-
1.5 mm (0.030-0.060 in.) of cable
free-play gap in the throttle lever.
If there is no cable free-play in the
throttle lever, the throttle safety
switches will not function prop-
erly, and the engine will cut out in
the idle position.
0741-518
! WARNING
Be sure to tighten the swivel
adapter jam nuts securely. If a
swivel adapter jam nut is not tight-
ened, the adjuster can rotate out of
the carburetor cap causing the pis-
ton valve not to return to the full-
closed position.
To Next Page
Loading...
