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.