Johnson J10RLSRD Service Manual page 163

FUEL SYSTEM
CARBURETOR MIXTURE ADJUSTMENT
25/30
MODELS
Make a reference mark on the carburetor body
before you disturb the needle adjustment.
Start the engine and run it in gear, at slow speed
(700 to 800 RPM) , for three minutes. Allow it to
reach normal operating temperature.
If the adjustment is too lean, the engine will
sneeze and backfire. Do the following procedure:
• Note the reference mark and turn the needle 1/8
revolution counterclockwise. Wait 15 seconds
after each adjustment and repeat this procedure
until you reach the highest consistent RPM .
If the adjustment is too rich , the engine will be
rough and unsteady. Do the following procedure:
• Note the reference mark and turn the needle 1/8
revolution clockwise. Wait 15 seconds after
each adjustment and repeat this procedure until
1. Reference mark
31856
you reach the highest consistent RPM.
Tiller Models
Face the steering handle. Turn idle speed adjust-
ment knob counterclockwise to lowest SLOW
speed position.
162
Test the adjustment. Run outboard near full throt-
tle for three minutes. Return the outboard to idle,
in gear. The outboard should maintain a smooth
idle RPM .
If the test results vary, repeat the adjustment.
If the outboard does not respond properly to these
adjustments, check the following :
• Engine temperature
• Linkage adjustments
• External recirculation system
• Sufficient exhaust back pressure