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[GastronomicKleptomaniac]

...yes, MrsGK's wonderful project Polo has already had me scratching my head.

Being of the younger generation (as those of you who've met me will testify, with my flowing curls and youthful face), I've only ever had cause to treat a carburettor as a sealed unit - ie remove it, don't touch any of those oh-so-twiddleable screws, and put it back where I found it. I understand the basic principle of vacuum causing fuel flow, it's all fairly common sense, but I'm lacking the practical experience.

I've ordered the Haynes Automotive Carburettor manual, having been told that it covers the 1B model fitted to the baby beast... I'm just wondering who I can start harassing on here when my best attempts to strip and rebuild it go pearshaped

Any donations to the "bin it and fit a Weber/ set of bike carbs/ V8" fund also appreciated

[biggriffin]

The common fault on those, engines was the rubber gasket, betwix carburettor and manifold, perishes, and causes to run lean and miss.

[GastronomicKleptomaniac]

The common fault on those, engines was the rubber gasket, betwix carburettor and manifold, perishes, and causes to run lean and miss.

I've heard that - I'm awaiting both the carb book and the Book Of Lies to arrive, so MrsGK can get it stripped and have a look. A, because it's her project, and more importantly B, because if it gets reassembled with a new gasket and still doesn't run quite right, I can't be blamed...

[Marks DTM Calib]

Not a lot goes wrong on the Pierburg 2E3 and 1B2 etc, is it auto choke or manual (the manuals were always better).

Basic adjustment only as well with idle mixture and idle....nothing else!

[omegod]

I recently did battle with a 2E2 on a scirocco that was incredibly frustrating, I stumbled upon a replacement that was know to run well so stuck it on and didn't touch it. I'd have stuck a weber on otherwise with a manual choke   

[GastronomicKleptomaniac]

Not a lot goes wrong on the Pierburg 2E3 and 1B2 etc, is it auto choke or manual (the manuals were always better).

Basic adjustment only as well with idle mixture and idle....nothing else!

Auto choke, the seller sort of hinted that he had had some chew with it. Gives Woman something to do!

[Marks DTM Calib]

I recently did battle with a 2E2 on a scirocco that was incredibly frustrating, I stumbled upon a replacement that was know to run well so stuck it on and didn't touch it. I'd have stuck a weber on otherwise with a manual choke

Pierburgs area a weber design made under license.....they are very very good carbs 

[Marks DTM Calib]

Not a lot goes wrong on the Pierburg 2E3 and 1B2 etc, is it auto choke or manual (the manuals were always better).

Basic adjustment only as well with idle mixture and idle....nothing else!

Auto choke, the seller sort of hinted that he had had some chew with it. Gives Woman something to do!

So what are the symptoms?

As other than main jet, idle jet, accelerator pump, float and float chamber plus the auto choke, there is little to them.

The manual chokes were always a lot better, they shut the choke fully for start and once there was some inlet vacuum an actuator cracked the choke butterfly open slightly, worked really well.

[Stargazer57N]

...yes, MrsGK's wonderful project Polo has already had me scratching my head.

 I understand the basic principle of vacuum causing fuel flow, it's all fairly common sense, but I'm lacking the practical experience.

Just to educate you a little on Carbs the fuel flow is not caused by vacuum as to create a vacuum you need a closed chamber so when the throttle is open this is not the case. The fuel flow is caused by the ventury effect, as air passes through the restriction of the throttle body [which looks something like this )(   ] it causes the air to move faster which in turns reducing the air pressure. Higher atmospheric air pressure acting on the petrol in the float chamber pushes the fuel though the jets.
Here endeth lesson one 

[aaronjb]

You did the easy bit Stargazer.. now do the rest of the theory 

I've read quite a bit about carbs (while deciding whether or not I wanted to run Holley carbs or FI on the kit car) and they're still a bit of a mystery to me - especially when you get to the rather infinitely adjustable carbs. I mean, look at this sucker: http://repairguide.autozone.com/znetrgs/repair_guide_content/en_us/images/0996b43f/80/21/22/83/large/0996b43f80212283.gif

Metering blocks, jets, screws, power valves, accelerator pumps, floats, bowls.. might as well be a foreign language 

[Marks DTM Calib]

That's a 4 barrel so hence effectively 4 carbs in one (well two twin chokes as it runs two mains and two secondary's)

Some of the bigger carbs have an additional jet which opens at or close to WOT to over fuel (in this case what looks at a quick glance to be a vac operated power valve e.g. low to no vac and it opens), nothing more complex than a standard carb.

[Mr Gav]

This thread brings back memories of my biking days and fitting Dynojet kits and fine tuning them with plug chops 

[Andy H]

I had a Mk2 Astra with the Pierburg 2E3.

The recurring problem I had was that the accelerator pump uses a diaphragm attached to a hollow actuating shaft which contains a spring and steel ball.

Press the accelerator and a lever presses on the steel ball and compresses the spring. The spring then applies pressure on the diaphragm to provide acceleration enrichment.

The problem is that the spring weakens or snaps - the accelerator pump appears to work but it does naff all unless you floor the throttle (and even then it doesn't provide enough enrichment)

Symptoms are that the car runs fine under all conditions except for that moment when you are pulling away from a standing start. The more important it is that you pull away smartly the greater the chance that the thing will cut out completely.