Contents: Checking the pump ↓ Disassembly, cleaning and inspection…↓ Installing the pump on the engine ↓
Fuel pump
1 – discharge pipe; 2 – filter; 3 – body; 4 – suction pipe; 5 – lid; 6 – suction valve; 7 – traction; 8 – manual fuel pumping lever; 9 – spring; 10 – eccentric; 11 – balance beam; 12 – lever for mechanical fuel pumping; 13 – bottom cover; 14 – internal spacer gasket; 15 – external spacer gasket; 16 – discharge valve
Checking the pump
Insufficient filling of the carburetor with gasoline may be due to a malfunction of the fuel pump, as well as clogged or damaged pipelines.
To find the cause of the malfunction, disconnect the hose from the discharge pipe 1 and use the lever 8 of the manual fuel pump to check whether fuel is supplied. If there is no fuel, then disconnect the hose from the suction pipe 4 and check whether a vacuum is created at the inlet of this pipe. If there is a vacuum, then the pipeline is probably damaged, and if not, then the pump is faulty.
Additionally, the fuel pump can be tested on a test bench. Rotating the drive shaft at a frequency of 2000±40 min⁻¹, check the pump flow (should be at least 54 l/h at 20±50°C) and the discharge pressure (should be 2.2–3.0 m of water column at zero flow). If you suspect a malfunction, disassemble the pump and check its parts.
Disassembly, cleaning and inspection of parts
1. To disassemble the pump, unscrew the cover mounting bolt 5, remove the cover and filter 2. Then unscrew the screws securing the housing to the bottom cover, separate them, remove the diaphragm assembly and spring.
2. Wash all parts with gasoline and blow with compressed air.
3. Check the integrity of the pump springs.
4. Check for valve sticking. Check the diaphragms. They should not be cracked or hardened. After checking, replace all worn or damaged parts with new ones. Replace damaged pump gaskets with new ones and lubricate with a thin layer of grease before installation.
Scheme of control and adjustment of the pump drive pusher protrusion
A – gasket thickness 0.27–0.33 mm;
B – gasket thickness 0.70–0.80 mm;
d – pusher protrusion
To properly install the fuel pump, use two of the three gaskets listed below: A 0.27–0.33 mm thick; In thickness 0.70–0.80 mm; With a thickness of 1.20–1.30 mm.
Installing the pump on the engine
1. Install the heat-insulating spacer on the cylinder block, placing gasket A between them, and place gasket B on the plane mating with the pump.
2. Measure the distance d using the device 67.7834.9506 (the minimum amount by which the pushrod protrudes, determined by slowly turning the crankshaft).
3. If the dimension d is within 0.8-1.3 mm, fix the pump to the engine, if d is less than 0.8 mm, replace gasket B with gasket A; if d is greater than 1.3 mm, replace gasket B with gasket C. Check dimension d again and secure the pump to the engine. There should always be gasket A between the cylinder block and the heat-insulating spacer.
The original source is located on the website VAZbook