Adjusting the idle speed of a warm engine
Before adjusting the idle speed, check that the ignition timing and valve drive clearances are set correctly.
Warm up the engine to operating temperature.
Connect the control tachometer according to the operating instructions.
Set the engine crankshaft speed at idle speed within 750-850 rpm by turning the mixture quantity adjusting screw 12 (see photo).
Connect the gas analyzer according to the operating instructions.
Remove the air cleaner cover and disconnect the crankcase ventilation hose.
Check and, if necessary, adjust the CO content using the idle mixture quality (composition) screw within the range of 0.5-1.2%.
Check and, if necessary, readjust the engine idle speed. Repeat these operations until the desired crankshaft speed and CO content are obtained.
Main parts of the Pierburg 2B5 carburetor:
1 - carburetor body;
2 - carburetor cover;
3 - needle valve;
4 - floats;
5 - float chamber gasket;
5 - main fuel jets;
7 - emulsion tubes with fuel and idle air jets;
8 — air jet of the transition system of the 2nd chamber;
9 — air jet of the transition system of the 1st chamber;
10 — idle mixture quantity adjustment bandage;
11 - electromagnetic shut-off valve;
12 — adjustment bandage for idle mixture quality (composition);
13 - throttle valve restrictor bandage;
14 — pneumatic drive of the throttle valve of the 2nd chamber;
15 - Automatic starting device;
16 - protective cap;
17 — pneumatic drive of the air damper;
18 — accelerator pump drive;
19 — accelerator pump piston rod pusher;
20 - accelerator pump;
21 - accelerator pump nozzle;
22 — throttle body.
Air filter parts:
1 - filter element;
2, 5 — thermostats;
3 - gasket;
4 — bracket;
6 — warm air supply hose;
7 — warm air damper;
8 - connecting hose;
9 — air intake pipe.
Operating principle of the pressure control regulator:
A - on a cold engine;
B - on a hot engine.
1 - bimetallic spring;
2 - drain fuel;
3 — control pressure supply;
4 — thermal winding of bimetallic spring.
Sectional view of the fuel electric pump:
1 — rotor;
2 - rollers;
3 - discharge tube;
4 - check valve;
5 - excess pressure valve;
6 — inlet chamber.
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