1980 Johnson 4HP Service Manual, Page 28Get this manual
Advance speed control until mark centered under rollerSee Figure 3-18 is
LOW SPEED NEEDLE ADJUSTMENT With motor at operation temperaturerun at slow speed (700-750 with test propeller in tank boatAdjust low speed knob until highest reading and smoothest performance obtained Allow 30 seconds for motor to respond to adjustmentPosition low speed knob so that the pointer is faeing down and push back to original position needle valveWith and needle valve correetly adjustedmotor should idle at 600
FUEL TANK
FUEL MIXTURE motor in exeellent mechanieal and operating condition, give faulty performance eause of improper fuel mixturePetroleum gum and varnish which preeipitate from stale mixture, clog the filter and small orifices thus interfering with starting and normal runningFor fuel mixture, see Seetion 2803093
1follower 2Mark 3Throttle 4adjusting screw
Figure 3-18Throttle
Adiustment