1975 Johnson 4HP 4R75, 4W75 Outboards Service Manual, Page 14Get this manual
TROUBLE
POSSIBLE CAUSE BMAGNETOSee Section Incorrectly adjusted pOints Loose wiring Coil or condenser damaged (loose) Fibre breaker block worn Points dirty or pitted Defective breaker cam Loose armature plate screws or worn pilot AMOTOR ADJUSTMENT Incorrect tilt angle BCAVITATION Protruding hull attachments Keel too long Transom too high CBOAT Improper load distribution Marine growth on bottom Added weight (water absorption) Hook in bottom Mis-matched boat and motor (boat underpowered)
3MOTOR MISFIRES (Assuming
Fuel SystemCarburetor OK) (Cont)
4POOR PERFORMANCE ON BOAT (Assuming Motor Runs OK)
SUBMERGED MOTORS
If motor is lost overboard while running, it should always be disassembled before any attempt is made to start itOften internal parts are