Arctic Cat 650 Twin2004, Service Manual

Page: 86 / 210

4-3
4
Carburetor
TROUBLESHOOTING
1. Drain float bowls into a clean, clear container.
Look for rust particles, water droplets, or other
contamination.
2. Momentarily turn the ignition switch to the ON
position. Fuel should resume flowing indicating
fuel supply to the carburetors is normal.
3. Dispose of the drained fuel properly; then move
the ATV outside or to a properly ventilated engine
run area.
4. Start the engine and warm up to operating
temperature; then attach a tachometer and adjust
the idle RPM to 1050-1150 RPM. Turn the
handlebar full left and full right. If RPM changes,
check for throttle cable adjustment or improper
routing.
5. Rock carburetors from side to side and note RPM.
Air leaks will cause RPM to increase. Tighten all
clamps, boots, and hoses. Inspect for cracks.
6. Check the air filter housing and air filter for water,
fuel, dirt, or other contamination. Wash or replace
if necessary.
7. Check pilot adjustment by turning pilot screws in
until lightly seated; then back out 2 1/4 turns. If no
change in RPM is noted as the screws are turned
in, check for an air leak between the carburetor
and the cylinder head.
KX025E
8. Check for proper carburetor synchronization by
attaching suitable vacuum gauges to the test ports;
then start the engine and increase the RPM above
idle. The gauges should read within 2 cm/Hg (0.78
in./Hg) of each other. Turn the synchronization
screw to equalize vacuum.
KX025C

NOTE: Idle RPM must be reset any time the syn-
chronization screw is adjusted.
REMOVING
1. Turn the gas tank valve to the OFF position.
2. Remove the seat; then drain the coolant.
3. Remove the storage compartment cover and air
filter housing cover; then remove the air filter.
4. Disconnect the hoses from the carburetors to the
gas tank valve connection.
5. Remove the screws securing the lower air filter
housing to the carburetors; then remove the lower
housing and tape over the carburetor inlets.
! WARNING
Whenever any maintenance or inspection is per-
formed on the fuel system during which there may
be fuel leakage, there should be no welding, smok-
ing, open flames, etc., in the area.
! CAUTION
Do not leave ignition switch on as fuel will be
pumped to the carburetors and a spill could
occur.
! CAUTION
Severe engine damage will occur if hardware
items or other foreign objects are ingested by the
engine on start-up.