Cause of malfunction - Remedy
Engine won't start
Clogged carburetor, fuel pump or fuel cleaning filters - Rinse filters
Pump diaphragm damaged or valves leaking - Replace diaphragm. Replace pump valve
Water frozen in the coarse and fine fuel filters or in the fuel lines - Warm up and blow with compressed air.
The float chamber fuel supply valve is stuck in the closed position - Flush the valve with gasoline, replace the sealing washer
Low mixture (clapping in the carburetor)
The choke does not close completely - Adjust the choke
Clogged carburetor jets - Rinse and blow jets
Intake manifold or carburetor gaskets punctured - Replace gaskets
Low gasoline level in carburetor float chamber - Adjust level
Exhaust gas recirculation valve stuck open - Replace EGR valve
Rich combustible mixture (claps in silencer)
Carburetor choke covered - Adjust choke
The tightness of the fuel supply valve is broken - Replace the valve seal
Clogged carburetor air jets - Blow out jets with compressed air
Fuel quality screw turned out too much - Adjust fuel supply
Elevated 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.
Faulty ignition coil - Check coil, replace if faulty
Faulty switch - Replace switch
There is no contact in the ignition circuit - Tighten the contacts.
Distributor defective - 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 the idle speed with the carburetor adjusting screws.
Valve clearances out of specification - Adjust valves
Faulty runner, distributor cover, or ignition coil - Replace the runner, check and replace the coil, replace the distributor cover
Intake pipe gaskets or carburetor gaskets broken - Replace gaskets
Faulty candles or one candle - Check faulty candles, replace
The tube of the vacuum regulator is not tight or, on the contrary, clogged or kinked - Check the tube of the vacuum regulator, replace if a malfunction is found
One or more cylinders are intermittent
High voltage wire breakdown - A bad high voltage wire can be seen by sparking in the dark.
Replace high voltage wire or wire set.
Distributor cover failure - Replace distributor cover
Faulty spark plugs - Replace faulty spark plug or set of spark plugs
Faulty coil - Check high voltage coil. Replace coil.
Increased toxicity of gases (engine smokes)
Ignition timing does not match specifications - Adjust timing
Worn valve stem seals - Replace valve seals
Increased wear of the cylinder-piston group - Repair the engine.