1980 Johnson 4HP Service Manual, Page 10Get this manual
SPECIFICATIONS Models J4WCS Weedless gearcase, standard Iength J4RLCS standard gearcase, long shaft
MISCELLANEOUS
Speed control Weight Single lever, synchronized throttl and Weedless38.0 Ibs(17.2 kg) Standard39.0 Ibs(18.3 kg) Automatic rewindnylon
POWERHEAD
(B.I.AFull throttl operat illg range est tank with test wheel 4000 to 5000 3800 Part No316021 for Weedless 4550 Part No317738 for Standard Idle Engine type and stroke Piston displacement Piston ring sets (2 standard 0.030" oversize Width of ring Piston assembIy standard 0.030" oversize Crankshaft si ze top journal center bottom journal Crank pin size set) Part Number 383920 Number 12 0.0625-0.0615 in(1.5881.562 Part Number 388726 Part Number 388728 600 2-cylinder, cycle Iternate fi ri ng 1-916" (39.69 1-38" (34.93 stroke 5.28 cubic inches (87 hp (2.8 kW) at 4500 Starter
IGNITION SYSTEM
Ignition Spark plug Spark plug gap Spark ug torque Flywheel magneto, breakerless C.DAC-M40FFX Champion L77 J4,14 .040 inch (1.0 17-1220-12 foot-pounds (2427 N.m) Part No581998