The new control unit is connected with a small additional harness to the same wiring block of the left mudguard, which was connected to the pneumatic valve control unit. The control unit is connected directly to the carburetor limit switch, bypassing the mounting block. The carburetor limit switch closes to the housing when the accelerator pedal is released. The addresses of the output terminals of the control unit 501.3761 are given in Table 14.
Table 14
| terminal No | Wire color | Address |
| 1 | TO | To the ignition coil terminal |
| 2 | H | On the body |
| 3 | 2 | — |
| 4 | ABOUT | +12 V |
| 5 | BC | Carburetor limit switch |
| 6 | SP | Carburetor electromagnetic valve |
| 7 | — | — |
Control unit 501.3761 should switch off the valve at a crankshaft speed of 1900 min⁻¹ and switch on at 1700 min⁻¹. When the accelerator pedal is pressed, i.e. when the carburetor limit switch is not closed to the housing, the valve should not switch off.
Disconnect the wire from the carburetor limit switch and short-circuit the tip of this wire with the housing. Connect a voltmeter to the control unit using an adapter connector. Start the engine and, gradually increasing the rotation speed, monitor the voltmeter readings: after starting the engine, it should show a voltage of at least 10 V, and at the moment the valve is turned off, a sudden drop in voltage to 0.5 V (no more).
The article is taken from an online resource (VazBook.ru)
Set the crankshaft speed to 2200-2300 min⁻¹, disconnect the tip of the wire going to the carburetor limit switch from the housing, and then reconnect it to the housing. When disconnecting the wire from the housing, the valve should turn on, and when connected to the housing, it should turn off. After turning off the valve, gradually reduce the speed until the valve turns on. The voltmeter should show a sudden increase in voltage of at least 10 V.