Fuel System Troubleshooting - Honda CB250N Shop Manual

Fuel
System
Troubleshooting
Afterburn
When
Engine
Braking
Is
Used
Lean mixture
in
slow
circuit
Backfiring
Or
Misfiring During Acceleration
- Ignition
system
faulty
- Fuel
mixture too lean
""
Poor Performance
(Driveability)
And
Poor Fuel
Economy
Fuel
system clogged
'
• Ignition
malfunction
Lean
Mixture
•
Fuel
jets
clogged
Ffoat valve faulty
•
Float level
too low
•
Fuel line restricted
•
Carburetor
air
vent tube clogged
•
Intake
air
leak
-
Throttle valve faulty
•
Vacuum
piston faulty
•
'
Rich Mixture
Bystarter valve
in
ON
position
'
Float valve faulty
''
.
Float
level
too high
.
..
•
Air jets
clogged
,
.
/
•
Air cleaner
element contaminated
A
Flooded carburetor
.
Engine
Stalls,
Hard To
Start,
Rough
idling
Fuel line restricted
-
Ignition
malfunction
.
•
Fuel
mixture too
lean/rich '
•
Fuel
contaminated/deteriorated
•
Intake
air
leak
Idle
speed
misadjusted
•
Float
level
misadjusted
• Fuel tank-
breather hofe clogged
•
Pilot
screw misadjusted
•
Slow
circuit
or bystarter
circuit
clogged
Engine
Won't
Start
•
Too
much
fuel
getting to the engine
—
Air
cleaner clogged
—
Flooded
carburetor
Intake
air
leak
•
Fuel
contaminated/deteriorated
No
fuel to
carburetor
—
Fuel strainer clogged
—
Fuel
tube clogged
—
Fuel valve
stuck
—
Float
level
misadjusted
—
Fuel tank breather hole
ciogged