Weber 32/34 cleaning jets

[Brenjacques]

Hi everyone,

It looks like the car has some dirt somewhere in the fuelling system, it's had some judders and near stalls over the last couple of days. I want to clean the jets on the weber whilst giving the fuel lines some attention and thought I'd ask for some advice before I do so.

Really I just want to know if it's just a case of unscrewing and pulling out the jets or am I likely to mess up any pre-sets in doing this? Will it be easier to take the carb off the car to remove them if needed, especially with the three part ones where I'll also need to remove the air corrector and emulsion tube. I'd prefer to take these out to clean and double check the sizes as when it was tuned the chap said the co screw was very sensitive which he hasn't noticed on these carbs before.

Apologies if the questions are a bit trivial, these webers are still quite new to me and much different to the SU's that I've messed around with in the past.

[chopperoli]

The beauty of this type of Weber is that you can access most of the important jets by just removing the air filter housing off the top. Each venturi has a main jet/air corrector/emulsion tube assembly which is removed as one piece.

My advice- first place a clean cloth in the carb venturis to stop anything falling into the engine. Clean out the carb top and jet recess area with compressed air before removing jets.

Only remove one jet/tube at a time. You'll have to put it back in the correct location, and also, less chance of dropping a jet in the adjacent well.

There is quite a good Haynes manual on the DMTL/DMTR series of carbs, worth finding a copy

[RussGLAuto]

Not a trivial matter at all.

Many cars have probably been given up on just for the want of clean fuel, mine included.

Suggest you find the source of the fuel contamination before cleaning the carb out, otherwise it will be a futile effort. Likely to be one or a combination of a rusty fuel neck contaminating the tank then the hard fuel lines under the chassis.

Tell tail will be minute black particles that the clear engine bay fuel filter will catch. Don't be fooled though thinking it's doing it's job. The filter won't stop everything. Hence the problem you have.

If you see this, then I'm afraid it's empty and clean out / replace fuel neck, tank and hard fuel lines. Then you can blow the carb jets through.

I had to do this with mine, but she's never missed a beat since.

[Brenjacques]

Thanks for that, I'll have to find a copy of the Haynes manual at some point. I've removed them and given them all a clean, they weren't bad anyway leading me to think that the blockage was in the fuel line which I've cleared.

Just as a side note, does anybody have the data on what the main jet sizes should be? The ones on my carb are 117 primary and 127 secondary. If memory serves me right these should be bigger but I can't find any info. The carb was bought new as a 1.8 version.

[Brenjacques]

Russ, our posts must have crossed as I was typing mine. I'll take a look at the tank, I know that the car is an older restoration and the tank probably a NOS replacement at the time, it still looks brand new from the outside and even still has paper VW stickers on. Whether the fuel filler neck was replaced I'm not too sure but I have my doubts due to the scarcity of them especially some years ago. Luckily my last fuel filter wax clear plastic so I could see there were no larger particles/specks in it although the yellow filter element had darkened to a grey/black colour

[RussGLAuto]

Tom's your man if you need a new filler neck...

https://dreadnoughtcustoms.co.uk/collec ... uel-system

Mine still looks brand spanking new after 4 years service!

Classic VW for new Mk1 Golf fuel lines - same as Mk2 Rocco. They also do tanks, but sounds like yours may just need a clean out:

https://www.classic-vw.co.uk/fuel-pumps ... -995-c.asp

My fuel lines looked perfect on the outside, but clogged with rust when removed...

Sounds like your filter is overdue a change too.

[mark1gls]

Best to change the fuel filter every year and they are not that expensive.