by Robert Kuhn
Between 1961 and 1974, VW used a variety of carburetors. They all work on the same general principle.
The fuel system consists of a front mounted fuel tank connected through a line to the fuel pump. An eccentric cam on the distributor drive shaft operates the mechanical fuel pump which delivers fuel to a downdraft type carburetor (ie: Solex).
All carburetted VW's use an oil bath type air cleaner (unless yours has been replaced with an aftermarket paper/foam element type).
There has been six different Sloex downdraft carburetors used between 1961 and 1974. Below is a brief description of each:
1961 - 1963
This was the first VW carburetor equipped with an automatic choke. A vacuum piston opens the choke butterfly slightly when the engine starts. This model has a power fuel system which means that it draws fuel directly from the float chamber under full load and high speed conditions.
1964 and 1965
This model is very much the same as the 28 PICT except that a vacuum diaphragm replaces the vacuum piston. This model also did not have a power fuel system.
1966 and 1967
This model is similar to the 28 PICT-1 except that it has a larger venturi. This model also does not have a power fuel system.
1968 and 1969
This model is like the 30 PICT-1 except that it does have a power fuel system.
This model is similar to the 30 PICT-2 except that redesigned idling permits the throttle to completely close at idel, while idle speed is controlled by air bypass around the throttle.
1971 - 1974
These two carburetors are similar to the 30 PICT-3 except a bypass mixture cuttoff valve replaces the pilot jet cutoff valve, and the venturi is larger. Although all 1971 thru 1974 carburetors are 34 PICT types, differing choke parts prevents interchangeability. On the 1972 models, preheating was improved and so a new element was used. These are identified with 60 on the choke cover.
|Removal and Installation.
Just about all auto part stores have some sort of carburetor cleaning solvent. Some come in the form of a spray can while others, the kind I use and recommend, come in a can (about the size of a paint can) which has a little basket inside the can in which to submerge your parts. A company called Gunk makes something called "Carburetor Dip", or at least they used to (it might be called something else now) which is what I use. It comes in a paint can with a small basket in which I can submerge my parts.
Use compressed air to dry the parts. If you don't have access to an air compressor, most auto part stores and electronic part stores (ie: Radio Shack) sell compressed air in a can which also works fine. Aside from the automatic choke, clean all the parts. Use a clean cloth to wipe the choke. To clean the jets (and all the drillings in the carb body), I recommend using compressed air rather than a piece of wire or pins. You can run the risk of enlarging the holes.
It's in the reverse order in which you took it apart.
I recommend using a rebuild kit when it comes to reassembling your Solex. They don't cost all that much, about $10.00 (US) the last time I checked, and they include everything but the float and jets. It's a good investment.
Other Solex's are similar
|1||Carburetor upper half screw||13||Diaphragm spring||25||Spring|
|2||Spring washer||14||Diaphragm||26||Pilot jet cutoff valve|
|3||Carburetor upper half||15||Gasket||27||Circlip|
|4||Float needle valve||16||Accelerator cable return spring||28||Fillister head screw|
|5||Needle valve washer||17||Carburetor lower half||29||Pump cover|
|6||Retaining ring screw||18||float and pin||30||Pump diaphragm|
|7||Retaining ring||19||Float pin bracket||31||Diaphragm spring|
|8||Retaining ring spacer||20||Air correction jet||32||Cotter pin|
|9||Automatic choke||21||Main jet plug||33||Washer|
|10||Plastic cap||22||Plug seal||34||Connecting rod spring|
|11||Fillister head screw||23||Main jet||35||Connecting rod|
|12||Diaphragm cover||24||Volume control screw||36||Accelerator pump injector tube|