Vento zipr3i, Service Manual

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Rev 01/ page120 of 143
Section 3.03 CARBURETOR
Complaint Symptom and possible causes Remedy
Trouble with
starting. 1. Starter jet is clogged.
2. Air leaking from a joint between starter body and
carburetor.
3. Air leaking from carburetor s joint s or vacuumed hose
joint.
4. Starter plunger is not operating properly.
Clean.
Check starter body and
carburetor for tightness,
and replace gasket.
Check and replace.
Check and replace.
Idling or low-
speed
troubles. 1. Pilot jet, pilot air jet is clogged or loose.
2. Air leaking from carburetor s joint, vacuum pipe joint, or
starter.
3. Pilot outlet is clogged.
4. Starter plunger is not fully close.
Check and clean.
Check and replace.
Check and clean.
Check and replace.
1) Complaint 2) Symptom and possible
causes
3) Remedy
Medium- or high-
speed trouble. 1. Main jet or main air jet is
clogged.
2. Needle jet is clogged.
3. Fuel level is improperly set.
4. Throttle valve is not operating
properly.
5. Fuel filter is clogged.
Check and clean.
Check and clean.
Check and replace.
Check throttle valve for operation.
Check and clean.
Overflow and fuel
level fluctuations. 1. Needle valve is worn or
damaged.
2. Spring in needle valve is broken.
3. Float is not working properly.
4. Foreign matter has adhered to
needle valve.
5. Fuel level is too high or low.
Replace.
Replace.
Check and adjust.
Clean.
Adjust and replace.
ELECTRICAL
4) Comp
laint
5) Symptom and possible causes 6) Remedy
No sparking or
poor sparking. 1. Defective CDI & ignition coil unit.
2. Defective spark plug.
3. Defective magneto stator coil.
4. Loose connection of lead wire. Replace.
Replace.
Replace.
Connect/tighten.
Spark plug soon
becomes fouled
with carbon.
1. Mixture too rich.
2. Idling speed set too high.
3. Incorrect gasoline.
4. Dirty element in air cleaner.
5. Spark plug loose.
6. Incorrect engine oil.
Adjust carburetor.
Adjust carburetor.
Change.
Clean.
Replace by hot type plug.
Replace.