Fuel pump
The mechanical fuel pump is driven by an eccentric on the intermediate shaft.
Characteristic | Meaning |
Vacuum pressure when the starter is turned on, kg/cm² | 0,332—0,465 |
| 0,095 |
Boost pressure when the starter is turned on, kg/cm² | 0,25—0,38 |
| 0,05 |
Stromberg carburetor
The M 102.920 and 939, M 115.954 engines were equipped with a single-chamber horizontal carburetor with constant vacuum Stromberg 175 CDT.
Calibration data
Characteristic | Meaning |
| Dosing needle marking | UC |
| Main fuel jet marking | 100 |
Idle fuel jet marking | 50 |
| Idle Air Jet Marking | 115 |
| Needle valve hole diameter, mm | 2,25 |
| Marking of the starting device cover | 200 |
| Fuel level in the float chamber, mm | 18—19 |
| Float weight, g | 11,8—13 |
| Oil grade in piston shock absorber | ATF |
| Shock absorber piston capacity, cm³ | 30 |
| Needle valve gasket thickness, mm | 1,5 |
| Starting clearance of the air damper, mm | 5,3±0,3 |
| Fuel delivery by accelerator pump per 1 cycle, cm³ | 1,9±0,15 |
| Engine crankshaft speed with vacuum regulator hose disconnected, rpm | 1250±50 |
| Clearance between the lever and the adjusting screw of the vacuum regulator, mm | 0,5 |
| Crankshaft speed at idle, rpm | 800±50 |
| Carbon monoxide content in exhaust gases, % | 1,0±0,5 |
| Crankshaft rotation speed at fast idle speed with engine oil temperature of 75–85°C and starting device sector position on the 2nd groove profile, rpm | 1700±100 |
| Carbon monoxide (CO) content in exhaust gases at fast idle speed with engine oil temperature of 75–85°C and starting device sector position on the 2nd groove profile, % | 6±1 |
| Time delay of electromagnetic shut-off valve, s | 6—16 |
Carburetor Solex DVG type 4A1
The M 123.920, M 123.921, M 115.938 and M 110.923 engines were equipped with a Solex DVG type 4A1 carburetor. The carburetor is an emulsion type, two-chamber, with sequential opening of the throttle valves, with an automatic starting device and a thermostatic auxiliary starting device (to start a warm engine). At forced idle speed, the forced idle economizer is activated.
Characteristic | Meaning |
Carburetor index | |
| E 17481 (E 17703)* |
| E 17482 (E 17704) |
| E 17603 |
* The index in brackets indicates the carburetors installed on models with an automatic transmission without a vacuum ignition regulator.
Since the 1980 model year, some characteristics of the Solex 4A1 carburetor have been changed.
Characteristic | Meaning |
| Fuel delivery by accelerator pump per 1 cycle, cm³ | 0,7±0,15 |
| Idle Air Jet Marking | 125 |
Accelerator pump nozzle marking | 50 |
Starting clearances of the air damper, mm | |
| 1,1 |
| 4,2±0,2 |
| Air damper opening, mm | 0,3—0,8 |
Calibration data for Solex 4A1 carburetor
Indicator | Car model "200" | |
1st chamber | 2nd chamber | |
| Diffuser diameter, mm | 20 | 54 |
| Needle valve hole diameter, mm | 2,0 | |
Main dosing system | ||
| x 97.5 | B5* |
| 2,147 | 3,747 |
Idle system | ||
| 42,5 | — |
| 120 | — |
Accelerator pump | ||
| 0,6±0,15 | |
| Float weight, g | 6,8±0,35 | |
Starting clearances, mm | ||
| 3,2 | — |
| 4,2±0,2 | |
| 2,9±0,2 | |
| Carbon monoxide (CO) content in exhaust gases | 0,5—1,5 | |
| Crankshaft speed at idle, rpm | 850—950 | |
Indicator | Car model "250" | |
| 1st chamber | 2nd chamber | |
| Diffuser diameter, mm | 20 | 54 |
| Needle valve hole diameter, mm | 2,0 | |
Main dosing system | ||
| x 97.5 | B7* |
| 2,147 | 3,747 |
Idle system | ||
| 42,5 | — |
| 115 | — |
Accelerator pump | ||
| 0,7±0,15 | |
| Float weight, g | 6,8±0,35 | |
Starting clearances, mm | ||
| 3,2 | — |
| 4,2±0,2 | |
| 2,9±0,2 | |
| Carbon monoxide (CO) content in exhaust gases | 0,5—1,5 | |
| Crankshaft speed at idle, rpm | 850—950 | |
Indicator | Car model "280" | |
| 1st chamber | 2nd chamber | |
| Diffuser diameter, mm | 20 | 54 |
| Needle valve hole diameter, mm | 2,0 | |
Main dosing system | ||
| x 97.5 | B5* |
| 90 | — |
Idle system | ||
| 42,5 | — |
| 110 | — |
Accelerator pump | ||
| 0,65±0,15 | |
| Float weight, g | 6,8±0,35 | |
Starting clearances, mm | ||
| 3,2 | — |
| 4,2±0,2 | |
| 2,9±0,2 | |
| Carbon monoxide (CO) content in exhaust gases | 0,5—1,5 | |
| Crankshaft speed at idle, rpm | 800—900 | |
* Marking of the jet needle.
Solenoid shut-off valve
Characteristic | Meaning |
Brand and type | Pierburg RE 20 273 |
Valve needle stroke, mm | 2,5±0,05 |
Nominal voltage, V | 12 |
Maximum allowable voltage, V | 16 |
Current consumption at terminal voltage of 12 V, A | 0,25±0,02 |
Vacuum regulator
Characteristic | Meaning |
Brand and type | Pierburg RE 20 464 |
Thermal valve for reducing toxicity of exhaust gases
Characteristic | Meaning |
Brand and type | Texas Instruments CARP or Pierburg PE 20213 |
Valve opening temperature, °C | 30±3 |
Valve closing temperature, °C | 20±3 |