Weber 32 DIR 109 carb??

[Havin-a-tug]

Hi all.

I'm after a Weber 32 DIR 109 carb for a 1990, 1.4, 340 auto.

I have a running problem with mine and I think this is the issue. One minute it runs smoothly and pulls well and then the next it's all lumpy and won't idle and at around 30mph it lurches. If I pull the choke out about half way it's fine for a while. I have checked vacuum hoses and all seem ok. I changed the top of the carb and it has got a bit better, but nothing near what it should be.

Before I changed the top of the carb the mixture screw was wound quite a way out. Once I changed the top it needed to be wound in much more and I thought I had solved the problem, but no This evening it seemed to be over fuelling, but how would that be? I thought the mixture was set by the screw and that was it?

Any help would be gratefully appreciated and if someone has a working carb then that would be great.

Cheers,

James.

[mac]

Very little can go wrong within a fixed jet carburettor to cause variably extant symptoms - most problems will give a specific but constant issue.
I assume that when you replaced the top you also checked for contamination, loose components and verified the float height?

Your troubles do rather point to uncontrolled variation in mixture (nb - the adjustment screw affects only the mixture a idle, by 1000rpm the primary barrel transition circuit is already in operation. Above idle mixture is "fixed" by the size of the jets and the amount of air being metered by the venturi. Unwanted air leaks from any source that bypass the venturi will result in a weakening of the AFR (your symptoms do suggest this).

Unlike (and contrary to popular belief) reports of basal warpage and air leaks with the 32DIR series are generally apocryphal (that being the prelediction of the Solex Z series) but still checks should be made.
Far far more likely with a CVT is the likelyhood of a fault with the vacuum system allowing air to be drawn into the inlet manifold affecting the engine mixture stability. "vacuum" leaks can appear not only with the hoses but also in other parts of the system e.g. across the primary diaphragms, within the 4way vac valve, via the clutch disengage servo and it's control valve, or on "all" versions the brake servo, CB pipe work (loss or blockage of the metering nipple), Renix vacuum reference line or even (on a 1986 car) the vac. operated heater air recirculation system.

Finding a replacement 109 (type 100 or 101) is certainly possible but without determining the underlying cause of your problems first might result in little progress. Refurbishment of your existing unit is also possible - but again - be sure it is the carb at fault.

Mac

[derskine]

Hi - I have one of these carbs, not tested however, and to reflect this I'm looking for £15.

[mac]

If "havin-a-tug" doesn't want it, and the main and top castings are undamaged I'll be happy to have it.

Mac

[bogbasic]

Daniel, be very careful now, I suspect MAC has less patience than I do about delivery times ;-0 ;-0 ;-0 ;-0

I posted in another thread that the problem will surely be with the idle solenoid??

[derskine]

I'm glad you are understanding Jon haha. I've forwarded you an email today.

Also RE the carb, I think havin-a-tug wants it.
There is another in the box of parts Jon is going to receive.

[derskine]

Hi Mac, I haven't recieved a reply from havin-a-tug yet so the carb is very much still available.
There's no damage to it but one of the brass screws that holds the accelerator pump on is missing.

[CBA]

There's no moisture in the distributor cap is there?

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You should idle in neutral and block off each vacuum hose one at a time/all simultaneously till it idles even or proven to make no difference . You'll likely find the fault.

Theres a few valves on the vac pipes too.. they like to be flushed with petrol (or a similar solvent). Good to take the rocker cover off and wash that out similarly.. and all the breather pipes.. and any vac pipes that have drawn in oil.

The seal between rocker cover and cylinder head is important, as are the bolts on the rocker cover itself. If these leak it doesn't like it. The engine is sensitive to crankcase pressure... The 1.4 can run silky smooth and like a fine machine. It's 40 years of evolution... it's as good as normal engines ever got... its was all downhill from the cleon fonte.


So the carb doesn't leak?

You can wipe a bit of gasket sealant evenly on both sides of the old carb (just thick enough to not be transparent) gasket (and wait for it to set before fitting the gasket (if you can rebuild a carb before 1/1000ths of a inch-thick layer of gasket sealant goes off)) to ensure a good seal - always had a success when doing this, others Will raise eyebrows.

Make sure the jets are clear, and the float is set right.

Modern gasket sealant is really useful. put it all together with care. check the inlet manifold is doing its job too and keeping extra air out of the air/fuel mix!! (check the colour of the plugs to see if theres a mixture imbalance..... if you get 500oC+ gasket sealant you can use it on pretty much everything including the intake manifold gasket. I've rebuilt them with gaskets only, with lab coat on.. and then rebuilt in anger with some sealant in the gaskets when it just wasn't having it.- Never had a 300 run so smooth and so economically as one KNOWN to be airtight throughout.

A compression test never hurt. - Its good to know the overall condition of the engine, you'll know its at least capable of running perfect then.