Cause of malfunction - Remedy
The engine does not start
The carburetor, fuel pump or fuel purification filters are clogged - Wash the filters, article - How to replace the fuel filter of a Gazelle car
The pump diaphragm is damaged or the valves are not sealing - Replace the diaphragm. Replace the pump valve, article - Repair of the GAZ-2705 power system with the ZMZ-402 engine
Water has frozen in the coarse and fine fuel filters or in the fuel lines - Warm it up and blow it with compressed air.
The float chamber fuel supply valve is stuck in the closed position - Wash the valve with gasoline, replace the sealing washer
Poor fuel mixture (pops into the carburetor)
The air damper does not close completely - Adjust the air damper
Carburetor jets are clogged - Wash and blow out the jets
Punctured intake manifold or carburetor gaskets - Replace gaskets
Low gasoline level in the carburetor float chamber - Adjust the level
Exhaust gas recirculation valve stuck open - Replace EGR valve
Rich fuel mixture (pops into muffler)
The carburetor air damper is closed - Adjust the air damper
Fuel supply valve seal is broken - Replace valve seal
The carburetor air jets are clogged - Blow the jets with compressed air
The fuel quality screw is too loose - Adjust the fuel supply
Increased level in the float chamber - Adjust the position of the carburetor float
The engine does not start in cold weather
The air damper does not close - Check visually by removing the air filter cover and adjust the air damper.
The ignition coil is faulty - Check the coil, replace if faulty
The switch is faulty - Replace the switch
No contact in the ignition circuit - Tighten the contacts.
Distributor faulty - Replace distributor
Unstable engine operation
The fuel level in the float chamber does not correspond to the specifications - Adjust the level.
Idle speed not adjusted - Adjust idle speed using carburetor adjusting screws.
Valve clearances do not meet specifications - Adjust valves
The slider, distributor cap, or ignition coil is faulty - Replace the slider, check and replace the coil, replace the distributor cap, article - Ignition system ZMZ-402 engine
Failure of intake pipe gaskets or carburetor gaskets - Replace gaskets
The spark plugs or one spark plug are faulty - Check the faulty spark plugs and replace them
The vacuum regulator tube is not sealed or, on the contrary, clogged or kinked - Check the vacuum regulator tube, replace if a malfunction is detected
One or more cylinders operate intermittently
Failure of a high voltage wire - A bad high voltage wire can be seen by sparking in the dark.
Replace the high voltage wire or set of wires.
Distributor cover malfunction - Replace distributor cover
Faulty spark plugs - Replace the faulty spark plug, or a set of spark plugs, article - GAZ-2705 spark plugs
Coil faulty - Check the high voltage coil. Replace the coil.
Increased gas toxicity (engine smokes)
The ignition timing does not correspond to the specifications - Adjust the timing
Wear of oil seals - Replace valve seals
Increased wear of the cylinder-piston group - Repair the engine.