Engine Does not Start


 Fuel is not Fed -to Carburetor

  • Vent knob is not open or vent clogged.
  • Fuel filter is clogged.
  • Fuel line is kinked.
  • Fuel line is connected improperly.
  • Fuel pump is faulty.
  • Primer bulb is faulty.
  • Check valve in connector is faulty

Fuel is Fed to Carburetor

  • Excessive amount of fuel, overflow
  • Carburetor vent is clogged.


Sparks Across Spark Plug Gap 

Insufficient sparks

  • Spark plug gap is small. Weak starter motor rotation. (Electric starter type)

Normal Sparks

  •  Recheck the fuel system.

No sparks – Across Spark Plug Gap

Spark plug is faulty.

  • Contamination
  • Incorrect gap
  • Broken spark plug
  • Pulser coil is faulty.
  • Current leaks from high tension cord
  • C.D.I. unit is faulty.
  • Exciter coil is faulty.
  • Ignition coil is faulty.
  • Wire harness is faulty.
  • Current leaks from engine stop switch cord.
  • Stop switch does not return satisfactorily.
  • Spark plug is improperly installed.
  • Emergency stop switch is improperly installed.
  • Shift lever is not in N position.

Engine starts but immediately stops. Engine some times stops while cruising.

No gasoline in fuel tank.
There is gasoline – in fuel tank.

  • Water is mixed with gasoline.
  • Vent knob is not open or vent is clogged.
  • Fuel filter is clogged.
  • Air screw IS open too L wide.
  • Idling speed is too slow.
  • Carburetor vent is clogged.
  • Fuel pump is faulty.
  • Air in fuel pump.
  • Air enters through fuel line connector.
  • Air enters through primer bulb.

Engine Overheats:

Normal sparking

  • Water intake screens are clogged.
  • Spark plug is not of specified rating.
  • Water pump is faulty.
  • Thermostat is clogged.
  • Thermostat is faulty.
  • Water tube or passage is clogged.
  • Exhaust gas is entering cooling system.