1978 Johnson 4HP outboards Service Manual, Page 17Get this manual
TROUBLE CHECK CHART (CONT) TROUBLE POSSIBLE CAUSE ASPARK PLUGSSee Section Cover or inner terminal damaged (spark plug terminal out of HTlead) Faul ty leads Looselow torque Incorrect heat range Defective (cracked insulator) BIGNITIONSee Section Loose or broken wiring Charge coil faulty Sensor coi faul ty Loose armature pi ate screws Power pack faul ty AMOTOR ADJUSTMENT Incorrect tilt angle BCAVITATION Protruding hull attachments Keel too long Transom too high CBOAT Improper load distribution Mari ne growth on bottom Added weight (water absorption) Hook in bottom Mismatched boat and motor (boat underpowered)
3MOTOR MISFIRES (Providing
Fuel SystemCarburetor OK)
4POOR PERFORMANCE ON BOAT (Providing Motor Runs OK)
SUBMERGED MOTORS