Beg/borrow/buy a Gunson colourtune if you can, very useful for determining the mixture strength. Could be you've left a vacuum line off or something silly like that.
Plug chop it perhaps?
If you are feeling brave, and have a can of lighter refill butane, bodge a normal spray nozzle on and spray butane into the throttle body with the engine running. If it smooths out, your engine is running way lean whereas if it gets worse, it is likely too rich. Is the automatic choke working correctly?
Could just be the carb is crudded up from standing, or if it has a diaphragm, that is pinholed.
That all assumes the elektwikkywy type sparknflash stuff is in top order.
Oh yeah, if it is the carb, Weber do a replacement. Much less aggro than Pierburg.
James Dore ( snipped-for-privacy@dsl.pipex.com) gurgled happily, sounding much like they were saying :
Give it plenty much welly, then cut it - at full throttle, full load, hit the clutch and kill the ignition suddenly. Coast to a stop, and pull the plugs out, so you can see the colour - and hence richness - under full throttle/load without having them change colour in the coast to a stop.
It's a lot easier just to get a gas analyser, but it won't tell you if the plugs are too hot/cold. You'd also miss out on the fun'n'games of burnt fingers and stripped plug threads...
Duncan Wood ( snipped-for-privacy@dmx512.co.uk) gurgled happily, sounding much like they were saying :
Surely a cheap disposable lighter would be just as good - if not better?
I'm sure we needn't say this, Steve, but you DON'T actually light it - just flow the gas and wave it around the manifold joints. If the engine speeds up, you've found false air.
I'd think that's more likely on an L-jet-style injected car, though, with a big flexible trunk between throttle body and plenum. On a carbed car, it's more likely to be crap in the carb or shagged out diaphragms.
I take it you've gone through the carb and done the basics? Plenty of cleaner and checked the float level, jets are clear etc?
Dunno if this'll help but I had a similar prob with a Scirocco 1.8 on a 2e2 carb. The thing ran fine but I had previously broken another car where the owner had refurbed and cleaned the carb, and used a manual choke kit.
I swapped the lot, got the choke to work pretty decently but I could never get that darn carb to run right - always coughed around 2k revs. I adjusted the hell out of it, cleaned everything again, checked for crud - never did get to the bottom of it.
I put the old one back on, repaired (bodged) the cold start mechanism and didn't look back.
You'll hear a lot about crud in VW fuel tanks and the like. In your case (as was mine) the carb may "look" fine but is far from it. Also, don't believe all you hear about the plug n play benefits of the Weber replacement. I know of a few blokes who went this route and couldn't live with the poor cold starts and carb icing in cooler weather.
Poor vacuum is the first place to look, but after that suspect the peirburg and its mixture.
Hmmmm, I'm _almost_ tempted to order a replacement carb for it, but I want to trawl the breakers first, as the 2B5 and 2E2 were used on a load of different VAG models right up until the early 90s.
Anyway, I've just ordered some new vacuum hoses and a waxstat this morning, so I'll have a look at those tomorrow (it's raining here this morning, so I'll have to leave it today).
Suppose I could wander down Halfrauds for a couple of Gunson bits and to see if I can get a decent-ish automotive multimeter.
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