5.3.5. Idling adjustment

Scheme of system of idling of the carburetor

1 – case of butterfly valves;
2 – butterfly valve of the first camera;
3 – openings of the transitional modes;
4 – the opening regulated by the screw of amount of mix;
5 – channel of air intake;
6 – adjusting screw of amount of mix;
7 – adjusting screw of structure (quality) of mix;

8 – emulsion channel of system of idling;
9 – adjusting screw of additional air *;
10 – carburetor case cover;
11 – air jet of system of idling;
12 – the case of a fuel jet of idling with the locking valve;
13 – fuel channel of system of idling;
14 – emulsion well.

* Is established on a part of carburetors.


We regulate system of idling with the purpose to provide steady turns of the engine idling with the minimum content of carbon oxide (SO) and hydrocarbons (SN) in the fulfilled gases. We recommend to perform this operation on points of adjustment "CO-CH".
For idling adjustment the carburetor has the quantity screw reducing or increasing amount of the mix coming to the engine, and the quality screw defining composition of mix (see the Description of a design).

At the plant on these screws of a napressovana restrictive plastic plugs.

They do not allow to break factory adjustments. It is possible to turn the screw of amount of mix with the restrictive plug no more than on 90 °, and qualities – on 50 ° that allows, without having a gas analyzer, only to arrange rotation frequency idling. If with plugs it is not possible to adjust idling, the screw-driver we break them and we repeat operation.
Adjustment is carried out with use of a gas analyzer on the engine which is warmed up up to the working temperature with adjusted by ignition and gaps in the drive of valves (see appropriate sections), at completely open air gate.
Establish by the screw of quantity on a tachometer the frequency of rotation of a bent shaft of 820-900 min. –1.

The screw of quality achieve concentration of CO in the fulfilled gases within 0,5–1,2% at this position of the screw of quantity.

The screw of quantity restore the frequency of rotation of a bent shaft up to 820–900 min.-1. If necessary the screw of quality restore concentration FROM 0,5–1,2%.