The fuel from the tank goes through the fuel line to the diaphragm pump.
It is driven by the camshaft eccentric, which acts on the pump drive lever. A fine brass mesh filter is installed on the pump inlet fitting.
When the engine is not running, fuel is pumped into the carburetor by the lever of the manual pump drive.
There is a hole in the lower part of the pump housing to monitor the integrity of the fuel pump membrane.
Removal and disassembly of the fuel pump
Conditionally, we remove the pump from the engine removed from the car.
With the head on 12, we turn off the two bolts of the fuel pump attachment
Removing the fuel pump
Remove the fuel pump gasket
We mark the relative position of the cover and parts of the fuel pump housing
Use a flat screwdriver to unscrew two screws
Remove the lid
Remove the sealing gasket.
Remove the strainer.
With a screwdriver, we unscrew the eight screws that tighten the halves of the case.
Disconnect the pump housing.
With the key "on 8" we turn off the nut of the stem, holding the upper washer of the membrane with sliding pliers
We remove the upper washer, three membranes, the lower washer and the spring.
If only the membranes are damaged, replace them and assemble the pump in reverse order
For complete disassembly of the pump, we remove the thrust washer of the membrane from the stem
We remove the thrust washer of the spring.
With the key "on 9" we turn off two screw plugs.
With a thin beard, we knock out the axis of the pump drive lever
We take out the drive lever, the lever sleeve and the spring
We take out the stem with a seal.
In case of damage, replace the rubber seal
Inspection and defecation
Rinse all pump parts in gasoline.
Inspect the pump housing. The threaded holes of the housing must not be damaged and the thread must not break.
There should be no warping in the area of threaded holes on the mounting flange of the pump head.
The control hole strainer must not be clogged or damaged.
Inspect the diaphragm. If there are cracks, tears or significant scuffs on it, it needs to be replaced.
Replace the torn strainer.
Check if there is no jamming of the valves in the pump head. If there is jamming, eliminate the causes or replace the fuel pump head.
It is more convenient to assemble the pump in the following sequence:
We install a thrust washer, spring, membranes and membrane washers on the rod.
Tighten the nut of their fastening.
We install the stem with the membranes into the pump housing and, having drowned the stem, insert the lever with the sleeve and spring.
The lever fork must engage with the rod (as shown in the photo).
Further assembly of the pump is carried out in reverse order.
When turning the screws connecting the halves of the housing, we combine the marks and press the lever of the manual drive up so that the membranes bend, and the holes of the membranes and the housing are aligned.
Pinching the outlet pipe with your finger, using the lever of the manual drive, we create pressure by lowering the pump inlet nozzle into the fuel.
After holding for 10-15 seconds, we release the finger. Fuel should splash out of the outlet pipe. Otherwise, tighten the screws connecting the housing and the pump cover, and re-check the serviceability of the pump.
If it was not possible to restore the pump's operability in this way, the valves are leaky. In this case, we change the pump assembly or half of the housing with valves.
We install the pump in the reverse order.
There is a drainage hole in the pump housing for draining fuel in case of damage to the membranes.
Therefore, after starting the engine and during its operation, it is necessary to monitor the absence of fuel leakage from this fuel pump opening.