1977 Evinrude 4HP Outboards Service Manual, PN 5303, Page 14Get this manual
TROUBLE
POSSIBLE CAUSE BIGNITIONSee Section Connectors Loose wiring or connections Ignition coil damaged Charge coil, sensor coil Grounded leads Loose sensor, charge coil plate screws or worn bearing 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 (Providing
Fuel SystemCarburetor OK) (Cont)
4P OOR PERFORMANCE ON BOAT (Providing Motor Runs OK)