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EMISSIONS SERVICE BULLETIN
Ref No. 12-01R
Issued in: Jan. 2012
Start and run the unit to warm up the engine. Engine must be at
operating temperature before completing Low speed mixture
needle adjustment. Warm up engine for minimum of 3.5
minutes by alternating between Wide Open Throttle (WOT) for
1 minute, then idle for 10 seconds.
■
Low Speed Mixture Needle (B) Adjustment
1) Set engine Idle Speed at 3800 +/- 50 RPM by turning Idle speed
throttle valve screw
(A)
. The engine RPM should be stable in the
3800 RPM range.
2)
NOW
adjust Low speed mixture needle
(B)
Clockwise (CW) Leaning
or Counter clockwise (CCW) Richening to reach Maximum engine
speed
AT IDLE
just before lean drop off, where RPM just begins to
drop.
3) If the idle speed at lean drop off is
HIGHER
than 3800 rpm. Adjust
Idle speed throttle valve screw
(A)
Counterclockwise (CCW) down
500 RPM.
4)
Repeat
step 2) and 3) as needed using 500 RPM step reduction,
until maximum lean drop off speed is reached and speed
AT IDLE
is
stable at 3800 +/- 50 RPM.
5) Turn
Low speed mixture needle
(B)
counterclockwise (CCW) in
1/8th turn increments and
Rich Down
the mixture 600 - 800 RPM to
reduce engine speed
AT IDLE
, down to 3000 RPM.
NOTE: Engine speed must be allowed to stabilize a minimum of
20 seconds after each 1/8th of a turn adjustment of Low speed
mixture needle to assure accurate tachometer readings.
Verifying Engine RPM Using Tachometer
■
Checking Maximum RPM
1) Accelerate engine to Wide Open Throttle (WOT).
2) Check the acceleration state of the engine speed, and make sure
that
MINIMUM
engine speed at
WOT
should be at 7500 RPM
3) After checking WOT RPM,
stop
the engine. To comply with the
Emission regulations, insert new limiter cap in the Low speed
mixture needle hole. Press new limiter cap deep into Low speed
mixture needle hole to prevent tampering.
4) Re-Start engine and verify engine Idle speed range from 2800 to
3200 RPM.
5) Verify Wide Open Throttle (WOT) engine speed range should be at
7500-8500 RPM
and the engine should idle and accelerate smoothly.
NOTE: If problem persists, check carburetor for dirt, varnish,
gum, moisture and corrosion contamination.
ATTENTION !!! IMPORTANT !!!
Carburetor adjustments with caps removed must be conducted by Authorized Emission Certified
Servicing Dealers ONLY. The dealer must supply the unit to the customer in the original
configuration, using
manufacturer’s carburetor adjustment procedure, which includes having the
limiter caps in place before the unit is put into service . Knowingly removing or rendering
inoperative a device, element, or design installed on or in a non-road engine which is in
compliance with E.P.A. or C.A.R.B. regulations is classified as TAMPERING.
TAMPERING is a violation of FEDERAL LAW, resulting in significant civil penalties (fines) of up to
$25,000 for each violation.
Low-Speed
Needle (B)
Idle speed
Throttle Valve Screw (A)
Idling
Full
Throttle
1st Time
2nd Time 3rd Time
New
Limiter Cap
Limiter Cap Tool
