1977 Johnson 2HP Outboards Service Manual, Page 17Get this manual
2LOSS OF POWER(Providing Ignition (continued)
GASES ENTERING COOLING SYSTEM See Section Damaged water tube grommet ring Exhaust housing to 10wer motor cover gasket damaged SPARK PLUGSee Section Cover inner terminal damaged (spark p1ug termina1 out of 1ead) Faulty 1ead Loose10w torque Incorrect heat range Defective (cracked insulator) MAGNETOSee Section Incorrect1y adjusted points Loose wiring Coil condenser damaged (loose) Fiber breaker block worn Points dirty pitted Defective breaker Loose armature p1ate screws worn armature plate liner MOTOR ADJUSTMENT Incorrect tilt angle (smoking) CAVITATION Protruding huH attachments Kee1 too long Transom too high Improper 10ad distribution Marine growth bottom Added weight (water absorption) Hook in bottom Mis-matched boat and motor (boat under-powered)
MOTOR MISFIRES (Providing Fue1 SystemCarburetor
4POOR PERFORMANCE ON (Providing motor is running