Carburettor overhaul

Posted by Jon July 13, 2012

Many poor running issues can be traced to the little dirty component on the top of your engine. Here’s what’s involved in rebuilding a stock Solex carburettor.

It might not look much, but your Bus won’t do much without one.

This is how you go about re-commissioning a stock Solex carburettor. VW used a very similar part right across its air-cooled model range and, while there are numerous variations on the theme, the principle for rebuilding is the same for all air-cooled motors.

The carburettor featured here is the Solex 34 Pict 3. This is probably the most common carb out there in VW land, as it’s the main staple of pretty much all air-cooled 1600cc engines. Even if your carb is different, you’ll find most rebuild kits are ‘universal’, so will include extra gaskets, washers and jets to cover most applications from the
1960s onwards.

Carburettor rebuild kits are readily available and inexpensive, especially when compared with the price of a brand new carburettor. The likes of Cool Air, GSF, Just Kampers and VW Heritage all stock them and they are priced at around £12.

Working on a stock Solex carb is also pretty simple, but we would advise you orientate yourself well with the whole unit first, and then with each item that you remove. And why not grab a digital camera and take pictures along the way to help when it comes to re-assembly time? If in any doubt, seek professional advice.

Whilst carburettors are fairly simple, they are precision instruments and reasonably complex in operation, so attention to detail is paramount. Miss one jet or sealing washer and your carburettor will not function correctly. Worse still, it may leak fuel, which could lead to an engine fire.

Removing a carburettor from an air-cooled VW engine is easy – simply remove the air filter first so you can see what you are doing. Then undo the accelerator cable, disconnect the choke and fuel cut-off solenoid wires, undo the clamp and withdraw the fuel pipe. The carb itself is secured to the inlet manifold by two 13mm nuts. Undo these and, hey presto, the carb will now come off in your hands (though try and keep the carb upright as there will be some residual fuel in the float chamber).

Disassembling a carburettor is also simple, and this feature covers the salient points.

So why might you want to rebuild your carburettor anyway? Well, over the years parts wear out inside the carb and erratic running will ensue. Rebuilding your carb will have your VW running like clockwork and save you dosh at the petrol pump. Which, these days, is of great importance to us all…

Feel free to download this article as a .pdf file so you can print it out and use it in your garage. However we do recommend reading the entire article first, so you can familiarise yourself with the procedure and know what your getting in to.
(To save the file to your computer right click the link below and select ‘Save file as’ or ‘Save linked file as’. If you click the link normally it will open in your browser.)

COST: DIY: £12-£15 (parts) or Pro: £90 (labour) plus parts
TIME TAKEN: 2 hours
DIFFICULTY:
TOOLS NEEDED: A selection of screwdrivers (both cross and flat heads), a 13mm and a 17mm spanner and a pair of needle-nose pliers