1971 Johnson 2HP outboards Service Manual, Page 23Get this manual
3-8 cRun engine at full throttleUsing tachometer, adjust high-speed needle until best high-speed setting is obtainedLo!-Speed Needle NOTE High-speed needle must be correctly adjusted as described above before low-speed needle adjustment is begunaWith motor at operating temperature, run at slow speed (700-750 rpm) with test propeller in tank: or on boatAdjust low-speed knob until highest rpm reading and smoothest performance are obtainedAllow 15 seconds for motor to respond to adjustmentAdjustment of highspeed needle MUST be repeated after final low-speed needle adjustmentbInstall adjustment knobsDO NOT disturb pOSition of needlePosition knobs so that each boss is pointing straight up and push back to original position on needlescWith cam and needle valves correctly adjusted motor should idle at 650 rpm