Do I have a mystery carburettor?

[Dickster665]

Kiwi, Please find attached below images of my carburettor for your perusal.





This is the first time I have removed the rubber inlet hose and I am concerned by the lack of any electrical wire to the male spade connector shown in one of the images. Should I be?
Cheers
Dicky

[Way2go]

This is the first time I have removed the rubber inlet hose and I am concerned by the lack of any electrical wire to the male spade connector shown in one of the images. Should I be?

It looks like a switch/sensor attached to the accelerator pump. Maybe to switch an overide on an electric fuel pump to keep it running full whilst you are flooring the pedal?
Of course its intended operation may not be applicable on the BX?

[electrokid]

No - you were right the first time - it's a mystery

Kidding

From the drawings you appear to have the top end of the DRTC - that itself is probably not a mystery - the Weber carb is 'modular and the C in DRTC probably stands for Citroen - it's likely that the top end is manufacturer specific.

Also the spec for the DRTM doesn't mention the 12 volt idle cut-off valve - the DRTC IS fitted with one but it's part of the top end - in you first pic it's the whiteish plastic thingy in the foreground with the wire attached.

It all looks pretty clean apart from the accelerator pump diaphram (which is seen in the first pic between the white plastic shut-off valve and the valve with the 12v connection 'missing'. Immediately below the accelerator pump diaphram there is a nut which is on the end of a control spindle and it looks as though a small amount of fuel has leaked from either the diaphram or the spindle onto the plate below - probably nothing much to worry about either uless you ever see fuel dripping onto the plate.

The thing with the 12v connection 'missing' looks to me like a vacuum device of some kind - not sure. But you do have COAS - in the last pic on the LH side - the valve with 2 pipes attached which is mounted at 30 degrees from the vertical.

The mystery thing with the 12v connection 'missing' looks like a diaphram of some kind - possibly anti-stall (which should be unecessary with COAS fitted). Anti-stall can be driven by vacuum or from a second output from the alternator (if this is the case then don't connect 12v to it as most secondary alternator outputs are 6 volt ! ) so it looks as though in this case it's driven by vacuum.

Or it could be something else

[Dickster665]

Thanks Elecrtrokid. It is good to know the carb is in relatively good condition. There is a smell of petrol in the car prior to starting but this soon dissipates once the engine is running. So your analysis seems about on the money that there is a tiny leak.

You will to excuse my ignorance here as all my knowlege of carbs has been gleaned from motorcycles. Is there a float needle valve that regulates fuel flow to the carb's float bowl? If one exists is it like motorcycle ones and prone to becoming unseated by dirt resulting in petrol being dischaged from and overflow pipe overnight ?

Thanks again for your assistance.

Dicky

[electrokid]

Well the carb looks in reasonable condition - let's hope it is. We need to find the fuel leak though.

Checks to do with the engine not running / cold. That nut I mentioned earlier is the end of the main control shaft - connected to the throttle - try to wiggle that about and look to see if any petrol comes out as you do so. If it feels as if there is any play in the spindle then it's likely you'll have to send the carb away for re-bushing - replacement of the shaft bearings - particularly the case if fuel is leaking from here.

There's a second cable attached to the carb - which cable is which ? The top one looks to me like the throttle and the lower one the auto box kickdown cable - or have you a manual choke fitted ?

The short light coloured cap at 90° to the plastic shut-off valve (to the left of it in pic 1 ) is the float chamber vent - have a look to see if there is any sign of petrol escaping from here - internally there is a de-fuming valve which discharges into this vent when it opens. There is an adjustment of this valve which I can't see in the pics - just as well really - I wouldn't recommend fiddling with it anyway. Petrol coming from here can be due to a number of things such as the inlet (float) valve faulty.

Have a look at the accelerator pump - try and operate it manually and see if any petrol comes out the sides - internally there's a diaphram which is sealed at the edges by a moulded rubber seal - you can see the edge of the rubber squashed between the 2 halves of the pump.

I'm still not sure what the 'connection missing' thing is but as Way2go said - it does seem to be mechanically connected to either the accelerator pump or the throttle spindle - it might - just might - be a throttle stop modifier - something that raises the tickover speed when aircon is switched on - or at least give it a tiny bit of throttle to compensate for the extra load or the aircon. Try to follow the 2 pipes to see whether they are vacuum pipes.

The only other thing I can think of at the mo is to run the engine for a few minutes then switch off and try to see if there any petrol leaks within a few minutes.

[Dickster665]

I have a manual choke fitted. It was installed before I bought the car.

One thing I haven't mentioned is that the car has done around 180000kms (113 000 miles) this may have relevance to the likely cause of the petrol leak.

I will go through your checklist when I have time and report back my findings.

The first major job, however , is to replace radiator, hoses etc. as I inherited a water leak from the previous owner that has incapacitated the vehicle. Flashing red light and not much water in the radiator. I have only driven it three times in three months, but enjoyed driving it as it has a fairly torquey engine. Unlike our Toyota Corolla (1999) that pleads to be revved but is however, bullet proof. Let's hope that it is not he head gasket!!!!!!!

Thanks again.

[electrokid]

Yes - the 1905 Peugeot lump seems to be bulletproof as long as regular oil changes are done - 113K miles shouldn't be a problem - I bought my 1905 diesel at around 140K and was happy it was such a low mileage

Check the fuel pipes from the petrol tank as well - if they are steel then where they bend around the bodywork just in front of the petrol tank they can rub and wear through - rubber pipes have their wear points too.

I'm beginning to think that the unconnected thingy is an 'economiser' - device that lets fresh air through to the manifold on the overrun. If so it's not part of the carb as such.