1970 Johnson 115 HP Outboard Motor Service manual, Page 16Get this manual
2-9 TROUBLE CHECK CHART (CONT)
TROUBLE 4ENGINE MISFIRES (Assuming
Fuel System and Carburetor OK)
POSSIBLE CAUSE
Faulty leads Loose spark plugs (low torque) Defective spark plugs (cracked insulator) Incorrect spark plugs BDISTRIBUTORSee Section Incorrectly adjusted sensor gap
Incorrect timing
Loose wiring Rotor pin missing lDose sensor Loose distributor base retainers Coil or pulse paCk
CORRODED OR CRACKED DISTRffiUTOR CAPROTORSee Section Rotor wave washer missing
Loose distributor ground wire Carbon path in distributor cap or rotor Loose or shorted sensor leads