1970 Johnson 1.5 HP Outboard Motor Service Manual, Page 15Get this manual
3MOTOR MISFIRES (Assurning Fuel SysternCarburetor
SPARK PLUGSee Section Cover inner terrninal darnaged (spark plug terrninal out of H.T.lead) Faulty lead Looselow torque Incorrect heat range Defective (cracked insulator) MAGNETOSee Section Incorrectly adjusted points Loose wiring condenser darnaged (looi'e) Fiber breaker block worn Points dirty pitted Defective breaker INCORRECT PROPELLER Incorrect tilt angle (srnoking) fueltoo(srnoking) Bent worn Exhaust outlet clogged exhaust housing (broken driveshafts) Bent gear housing Altitude horsepower 10ss Exhaust leaks Overheating CAVITATION Protruding attachrnents too 10ng Bent (vibration) Transorn too high Irnproper 10ad distribution Marine growth bottorn Added weight (water absorption) Hook in bottorn
4POOR PERFORMANCE ON
SUBMERGED MOTORS