Backfire - Kohler KG2204 Service

3.7. Backfire

Definition: The fuel ignites in the intake manifold, or in
the exhaust system, making a loud popping noise.
WARNING
Risk of Fire. Can cause severe injury or death.
Do not smoke or permit flames or sparks near fuels or the
fuel system.
Servicing the air cleaner. A sudden backfire can cause
severe injury or death. Do not operate the engine with
the air cleaner removed.
Checks
Preliminary Check
Ignition System Checks
Engine Mechanical Check
Figure 3-9 Backfire Troubleshooting
TP-6903 5/16a
Action
None.
 Check for proper ignition output voltage with a spark tester.
 Check the spark plug leads by connecting an ohmmeter to the ends of each lead in
question. If the meter reads over 15,000 ohms, replace the leads.
 Check the connection at ignition coil.
 Check for deteriorated spark plug lead insulation.
 Remove the plugs and inspect them for the following conditions:
o Wet plugs (oil fouling).
o Cracks.
o Wear.
o Improper gap.
o Burned electrodes.
o Heavy deposits.
 Check the engine for the following:
o Improper valve timing.
o Engine compression.
o Manifold vacuum leaks.
o Intake manifold gaskets.
o Sticking or leaking valves.
o Exhaust system leakage.
WARNING
Electrical shock can cause injury.
Do not touch wires while engine is running.
Fuel System Troubleshooting 53