CARBURETION WITH DIFFERENT CLIMATIC CONDITIONS
Condition
Cold
Hot
Dry
Wet hot
High altitude
Result
Lean
Rich
Lean
Rich
Rich
Required adjustment
To make richer
To make leaner
To make richer
To make leaner
To make leaner
Parts to use
MJ or NJ
it
a
ii
a
CARBURETOR TUNING BY BIFFEREWT FAILURE SYMPTOM
SYMPTOM
With full throttle;
• Rev peak too low
• Doesn't rev up quickly
• Poor power output (Rich)
With full throttle;
1 • Hesitates
• Pings or knocks
• Revs up out power not
sufficient.
Performs dull or inter-
j mittent in range 1/4
—
3/4
throttle opening.
Hesitates in range 1/4
—
3/4
throttle opening and torque
is poor.
Responds to gradual but not
to quick throttle opening.
Responce too sharp to
control
AJUSTMENT
• Decrease MJ size.
• Decrease gradually by 1 —
2 sizes while observing
piston crown color.
© Decrease PWJ size.
® Increase MJ size.
« increase gradually by 1 —
2 sizes while observing
piston crown color.
• Increase PWJ size.
Decrease NJ size to make
mixture leaner.
Increase NJ size to make
mixture richer.
Decrease MJ size because of
too rich main system.
Increase PJ size or lower JN
position*
REMARKS
• Check if choke is on.
• Check if not overflowing.
• Check if air not leaking in.
• Check if ignition timing not too
fast.
(Rich at a partial opening)
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