Carburettor; Idling Speed Adjustment - Vaz Lada Niva 1600 Maintenance Manual

Lada Niva Manual - Maintenance

Carburettor

Every 10.000 Km (and also after the first 2,000-3,000
Km if the car is new), wash the carburettor fuel filter and
the fuel pump filter with gasoline and blow them out with
compressed air.
Every 20,000 Km clean the carburettor from the inside,
wash it with gasoline or benzene and blow out with
compressed air. When cleaning the calibrated orifices of
the jets, use a wooden stick or match with a pointed end
wetted with acetone. Do not use wire, even soft, not to
disturb the dimensions and finish of the orifices. When
screwing the jets in or out, avoid damaging the thread in
the holes.
Check and, if necessary, adjust the fuel level in the float chamber and the float travel, for
which purpose.
• Make sure that the mass of float 9 (Fig. 36) complete with arm 7 is 12+1 g, the float has no
holes or dents, and can freely rotate on its pin.
• Make sure that seat 2 of needle valve 4 is tightened reliably and that damper ball 5 built
into needle valve 4 does not stick
• Set upper body 1 vertically so that the fuel inlet union is directed upwards, the needle
valve is closed, and float tongue 8 lightly contacts the needle valve ball.
• With the parts in this position, measure the distance between the float and the surface of
gasket 10 which fits the upper body; the distance should be 6.5 mm
• Change the position of the tongue, if necessary, to obtain the required distance; the tongue
must be perpendicular to the valve axis, and the contacting surface of the tongue should
have no defects that may cause sticking of the valve.
• Check the float travel which should be 8 mm, changing the position of stop 3, if necessary.
• Check that pull-back yoke 6 of the needle valve does not interfere with free travel of the
valve.
• Reinstall the carburettor upper body after making sure that the float is free to move without
brushing against the chamber walls.
Note. When replacing the needle valve, also replace the gasket between the seat and the upper body.

Idling speed adjustment

Every 10.000 Km (and also after the first 2,000-3,000
Km if the car is new), adjust the minimum idling speed
of the engine. Have this adjustment done at a service
station. The Owner is allowed only to carry out fine
adjustment of the engine idling speed within the range
permitted by idle speed screw limiting bushing 1 (Fig.
37) and by idle mixture screw limiting bushing 2.
Attempts to turn the bushings through a larger angle
will destroy them. In this case the Manufacturer bears
no responsibility for excessive content of carbon
monoxide (CO) in the exhaust gases and for excessive fuel consumption.
Perform the fine adjustment with the engine warmed-up, valve clearances adjusted, and a
spark advance angle set properly. Proceed as follows.
• Start the engine and turn idle mixture screw limiting bushing 2 all the way out.
• Using idle speed screw limiting bushing 1, set the engine speed within 850-900 rpm
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Fig. 36.Adjusting Fuel Level In Carburettor
Float Chamber: 1- carburettor upper body, 2 -
needle valve rest, 3 - stop, 4 - needle valve, 5-
ball, 6- pull-back yoke, 7—arm, 8—lounge, 9-
float, l0- gasket.
Fig 37. Idling system adjustment screws: 1- Idle
speed screw limiting bushing, 2- idle mixture screw
limiting bushing.
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