Checking and cleaning a GM Varajet carburettor
The Varajet carburettor used on many Vauxhalls and Opels is a hybrid between fixed-jet and variable-jet (for example, SU) types. It is as sensitive to dirt and sediment as any fixed-jet carburettor, and needs careful cleaning about once a year.
The Varajet has two chokes or barrels. The first, which works alone at low engine speeds, has a fixed-jet system. The second, which comes in at higher speeds, has a variable jet.
As with any carburettor, remove it from the car (See Removing a carburettor for cleaning) for cleaning. Wash parts in petrol, using lint-free rags to wipe them. Renew all gaskets. After reassembly, oil the external moving parts.
The carburettor has the layout of a normal fixed-jet type, and is dismantled in much the same way.
Take the same precautions against dirt and the loss of small parts (See Checking and cleaning a fixed-jet carburettor). Make notes or drawings of any parts dismantled, to aid refitting.
Try not to disturb the settings of adjuster screws, but if you do, ensure that you return them to their original setting by counting the number of turns taken to remove them.
Rinsing out the float chamber
Lift out the upper packing piece. Examine the float valve to see how the valve spring hooks on to its platform.
Unhook the spring and remove the float pivot clip so that you can lift the float out. The needle will come too, hanging from the end of the float. Lift it off.
Pull out the lower packing piece to leave the float chamber empty.
Rinse out the chamber with a little petrol and wipe it clean with a lint-free rag. Remove all sediment, but do not bother about surface staining.
When refitting the float, remember to hook the valve spring back into place. The float level is not adjustable.
As with any carburettor, the various parts are a precision-fit, and care must be taken to handle every part gently.
Before finally tightening the screws holding the carburettor top, ensure that the accelerator-pump piston moves freely.
Checking a Ford VV carburettor