mixture adjustment.

[taximark]

Having nearly killed a friends dog with the rich petrol smelling fumes
from my 2+2 yesterday, I think it is about time I sorted the mixture
out. The car runs pretty well, plenty of power (for a 1.4!!) and nice
smooth delivery across the entire throttle range. Fuel economy is good
(30+ mpg). There is also a really satisfying burble from the exhaust
on deceleration. However the exhaust stinks of unburnt petrol. I have
the 1986 1.4 cvh engine in the car with what I believe to be a
standard carb setup. It certainly has the standard air box and filter
fitted. The manual choke operates correctly so that isn't the issue.
The bit that confuses me is that the car went through its MOT
emissions test without a problem (though there was an england world
cup game on the radio at the time!). The car does a reasonable mixture
of local and distance runs and approximately 3-400 miles a week.

I am not able to obtain a tuning kit for the car at the moment as
funds don't allow so can anyone give me any guidance on how to adjust
the mixture to some approximation of correct, or at least so I am not
throwing large amounts of Shells finest out of the exhaust without
extracting the maximum bang from it first! (maybe it will save me
enough cash to get it done properly!!). I know that it is a bit of a
stab in the dark without the right kit but I am sure someone on here
will have some useful ideas.

Cheers Guys

Mark

[Ian Harrison]

Having gone through the mot ok, the first thing I would take a look at would be all the flexible petrol hoses. They have a nasty habit of degrading over time.

Kermit used to stink the garage out all the time until I sussed out that all the flexible hoses under the bonnet were acting more like sponges...
Ian

Sent from my iPad

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[Mark Miles]

Thanks Ian, 

Under the bonnet smells fine, either when running or not. the petrol smell is definitely from the exhaust.

Mark

---

From: Ian Harrison <bigha...@googlemail.com>
To: "quantu...@googlegroups.com" <quantu...@googlegroups.com>
Sent: Sat, 23 October, 2010 10:47:01
Subject: Re: [Quantum Owners] mixture adjustment.

[Susan and Martin Scott]

Does it go once the engine has warmed up?

----- Original Message -----

From: Mark Miles

To: quantu...@googlegroups.com

Sent: Saturday, October 23, 2010 11:09 AM

Subject: Re: [Quantum Owners] mixture adjustment.

Thanks Ian, 

Under the bonnet smells fine, either when running or not. the petrol smell is definitely from the exhaust.

Mark

---

From: Ian Harrison <bigha...@googlemail.com>

To: "quantumowners@googlegroups..com" <quantu...@googlegroups.com>

> For more options, visit this group at http://groups..google.com/group/quantumowners?hl=en

>
> IMPORTANT NOTE: All information presented herewith is provided on an "As Is" basis, without warranty or the implication thereof. Neither the Quantum Owners Club nor the individuals associated with the Quantum Owners Club or in the preparation of the above information shall have any liability to any person or entity with respect to liability, loss, or damage caused or alleged to be caused directly or indirectly by the instructions contained within this or related message(s).

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IMPORTANT NOTE: All information presented herewith is provided on an "As Is" basis, without warranty or the implication thereof. Neither the Quantum Owners Club nor the individuals associated with the Quantum Owners Club or in the preparation of the above information shall have any liability to any person or entity with respect to liability, loss, or damage caused or alleged to be caused directly or indirectly by the instructions contained within this or related message(s).

---

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[Mark Miles]

It is not as bad but still much too strong, comment was passed by a friend who was in the car behind me about it and that was after I had completed an 80 mile trip.

Mark

---

From: Susan and Martin Scott <susanan...@corringham99.free-online.co.uk>
To: quantu...@googlegroups.com
Sent: Sat, 23 October, 2010 11:21:24

[Susan and Martin Scott]

Hmm..... Strange how it didn't show up on emmission test - although I've been sceptical of MOT equipment for a long while. 3 previous cars have shown zero CO at MOT! That's an ancient Reliant Kitten, a fiesta 1100, and a Ka (the only catalysed one). Their equipment is only calibrated every 6mths. (every day or more frequently is auto-industry norm).

Have you examined the plugs after a long run? Should be a weak milk chocolate deposit, as opposed to black 

[Mark Miles]

The plugs come up very sooty, only checked them this week and it was after a trip of about 40 miles.

Mark

---

From: Susan and Martin Scott <susanan...@corringham99.free-online.co.uk>
To: quantu...@googlegroups.com

Sent: Sat, 23 October, 2010 12:40:13

[Susan and Martin Scott]

So it's definitely running very rich. Getting back to your original question ie how to adjust, it used to be explained in the old haynes manuals (maybe in one you have?). You may have to remove anti-tamper plugs to gain access to the screws?, but it's a case of engine at normal running temperature, increase idle speed with stop screw, then adjust mixture to correct - If you've not done this before, it can take some practice, but you'll find if you unscrew too much (ie let in more fuel) it will 'hunt' (sort of cough-chugg), screw it in too far, and you starve the engine of fuel and it'll die fairly quickly. Just get it about midway between the two situation. Step 2 reduce the revs a bit and repeat exercise, keep going until you get  no further improvement or your hands get too cold! Verify next time after a run by checking plug(s) Hope that helps, Martin

[Mark Miles]

wish me luck as I head out the door, screwdriver in hand.

Mark

---

From: Susan and Martin Scott <susanan...@corringham99.free-online.co.uk>
To: quantu...@googlegroups.com

Sent: Sat, 23 October, 2010 13:59:28

[Michael...@aol.com]

In case you run out of luck Gunson used to sell a gadget which was a special spark plug with a transparent bowl which enabled you to see the colour of the burning air fuel charge. A bit like adjusting a basic bunsen burner in a lab it had a colour chart so that you could judge the effect of your adjustments to the mixture visually.

 

I don't know if it is still available or if they had one that fits Fiesta size spark plug holes and threads

[Jim Hearne]

They certainly did do one that fits the CVH but you needed the version with the angle mirror on so you could see the flame down the deeply recessed CVH spar plug holes.

Jim

On 23/10/2010 22:56, Michael...@aol.com wrote:

In case you run out of luck Gunson used to sell a gadget which was a special spark plug with a transparent bowl which enabled you to see the colour of the burning air fuel charge. A bit like adjusting a basic bunsen burner in a lab it had a colour chart so that you could judge the effect of your adjustments to the mixture visually.

 

I don't know if it is still available or if they had one that fits Fiesta size spark plug holes and threads

[Gary]

http://www.gunson.co.uk/item.aspx?cat=673&item=1822

Have used one on many engines although not on a zetec.

Gary

On 23/10/2010 22:56, Michael...@aol.com wrote:

In case you run out of luck Gunson used to sell a gadget which was a special spark plug with a transparent bowl which enabled you to see the colour of the burning air fuel charge. A bit like adjusting a basic bunsen burner in a lab it had a colour chart so that you could judge the effect of your adjustments to the mixture visually.

 

I don't know if it is still available or if they had one that fits Fiesta size spark plug holes and threads

[Mark Miles]

I will be buying one on Monday, assuming I can find the mixture adjust screw before then. I discovered today that I have a Weber carb on the car but despite intensive googling I can't find the location of the mixture screw(s). I have also used colortune before.... 20 years ago on a Rover V8. It seems a little odd but apparently the instructions are now in black and white. That could make matching the colour interesting!

Mark

---

From: Gary <gary_bro...@blueyonder.co.uk>
To: quantu...@googlegroups.com
Sent: Sat, 23 October, 2010 23:10:38

Subject: Re: [Quantum Owners] mixture adjustment.

[Michael...@aol.com]

In a message dated 24/10/2010 00:00:26 GMT Daylight Time, taxi...@yahoo.co.uk writes:

I have a Weber carb on the car

If it is 1987 or later the mixture screw should be to the left and a little below the idle speed screw.

The idle speed screw is mounted at an angle - head downwards and has a coil spring acting as a locking device.  the mixture screw may be concealed behind a blocking plug so from the exterior it may just appear as a blanked off tube moulded as part of the carb body.  remove the plug to reveal the slotted screw head.

 

The Haynes manual also notes that when adjusting the idle speed screw the electric fan should be kept running all the time.

 

Michael

[Mark Miles]

This seems to be the problem I am having with finding a diagram for the carb as it is an '86 model cvh so I am guessing that the carb is probably an aftermarket unit or grafted on from a later engine. The carb has twin barrels and the idle adjust screw is a thumbwheel type which is parallel to the ground. There is a Weber tag attached to the carb but it has not aged  well and is mostly unreadable. I would have expected the mixture screw to be in the area you point out but can see neither a screw nor anything resembling an appropriate orifice to contain one. If all else fails then I shall have to remove the carb, find the screw then refit it to set it up which seems a disproportionate amount of work for an engine that appears to be running well.

 

Mark

---

From: "Michael...@aol.com" <Michael...@aol.com>
To: quantu...@googlegroups.com
Sent: Sun, 24 October, 2010 0:46:45

Subject: Re: [Quantum Owners] mixture adjustment.

--

[rus...@quantum54.freeserve.co.uk]

Are the barrels square or round? Mine has a thumbwheel for adjusting
the idle and that is a TLDM carb used on the later XR2s

Russell

On 24 Oct, 09:53, Mark Miles <taxim...@yahoo.co.uk> wrote:
> This seems to be the problem I am having with finding a diagram for the carb as
> it is an '86 model cvh so I am guessing that the carb is probably an aftermarket
> unit or grafted on from a later engine. The carb has twin barrels and the idle
> adjust screw is a thumbwheel type which is parallel to the ground. There is a
> Weber tag attached to the carb but it has not aged  well and is mostly
> unreadable. I would have expected the mixture screw to be in the area you point
> out but can see neither a screw nor anything resembling an appropriate orifice
> to contain one. If all else fails then I shall have to remove the carb, find the
> screw then refit it to set it up which seems a disproportionate amount of work
> for an engine that appears to be running well.
>
> Mark
>
> ________________________________

> From: "MichaelHughe...@aol.com" <MichaelHughe...@aol.com>

> To: quantu...@googlegroups.com
> Sent: Sun, 24 October, 2010 0:46:45
> Subject: Re: [Quantum Owners] mixture adjustment.
>

> In a message dated 24/10/2010 00:00:26 GMT Daylight Time, taxim...@yahoo.co.uk

> writes:
> I have a Weber carb on the car
> If it is 1987 or later the mixture screw should be to the left and a little
> below the idle speed screw.
> The idle speed screw is mounted at an angle - head downwards and has a coil
> spring acting as a locking device.  the mixture screw may be concealed behind a
> blocking plug so from the exterior it may just appear as a blanked off tube
> moulded as part of the carb body.  remove the plug to reveal the slotted screw
> head.
>
> The Haynes manual also notes that when adjusting the idle speed screw the
> electric fan should be kept running all the time.
>
> Michael--
> You received this message because you are subscribed to the Google Groups
> "Quantum Owners Group" group.
> To post to this group, send email to quantu...@googlegroups.com
> To unsubscribe from this group, send email to
> quantumowner...@googlegroups.com

> For more options, visit this group athttp://groups.google.com/group/quantumowners?hl=en

[Mark Miles]

I have looked at a pic of the TLDM, very similar but the top of the carb is not round. I will keep looking at pretty pics of carbs on the web, I am sure that I shall stumble across the right one eventually.... I hope.

 

Mark

---

From: "rus...@quantum54.freeserve.co.uk" <rus...@quantum54.freeserve.co.uk>
To: Quantum Owners Group <quantu...@googlegroups.com>
Sent: Sun, 24 October, 2010 10:03:27
Subject: [Quantum Owners] Re: mixture adjustment.

For more options, visit this group at http://groups.google.com/group/quantumowners?hl=en

[rus...@quantum54.freeserve.co.uk]

The other ones normally used were the DFT from the earlier car as it
gave better performance and the DMTR which was a Weber upgrade for the
XR2. I have a DMTR in the garage and can take a photo and send it to
you so that you can compare. If it is the right one it wiuld save you
taking your carb off.

Russ

On 24 Oct, 10:20, Mark Miles <taxim...@yahoo.co.uk> wrote:
> I have looked at a pic of the TLDM, very similar but the top of the carb is not
> round. I will keep looking at pretty pics of carbs on the web, I am sure that I
> shall stumble across the right one eventually.... I hope.
>
> Mark
>
> ________________________________

> From: "russ...@quantum54.freeserve.co.uk" <russ...@quantum54.freeserve.co.uk>

[Mark Miles]

Thank you, the pointers you gave me took me to the weber application list, a little googleing and it would appear to be a DFTM.

 

Mark

---

From: "rus...@quantum54.freeserve.co.uk" <rus...@quantum54.freeserve.co.uk>

To: Quantum Owners Group <quantu...@googlegroups.com>

Sent: Sun, 24 October, 2010 10:38:45

For more options, visit this group at http://groups.google.com/group/quantumowners?hl=en

[bill green]

Hi Mark, don't know if this will be any help, but at my last MOT my emmissions were high, the tester kindly adjusted these as I couldn't find the screw,it was in what was effectively the mounting flange for the carb,quite well hidden if you don't know where to look and certainly not obvious. Regards Bill
 

---

Date: Sun, 24 Oct 2010 10:20:10 +0100
From: taxi...@yahoo.co.uk
Subject: Re: [Quantum Owners] Re: mixture adjustment.
To: quantu...@googlegroups.com

[Mark Miles]

Having now looked at a blowup of the carb it would appear that the only adjustment is on the idle mixture. As the car appears to be running rich across the entire rev range I would assume that in order to sort the mixture I would be looking at re-jetting the carb or getting more air into the engine. I have the standard air box and filter on the car at the moment but I did notice that it appeared to be significantly leaner with the box off. Would it make that much difference if the carb had been jetted for use with some sort of induction kit? Personally I wouldn't have thought it would have made that much difference until you got into forced air solutions.

 

Mark

---

From: "rus...@quantum54.freeserve.co.uk" <rus...@quantum54.freeserve.co.uk>

To: Quantum Owners Group <quantu...@googlegroups.com>

Sent: Sun, 24 October, 2010 10:38:45

For more options, visit this group at http://groups.google.com/group/quantumowners?hl=en

[Steve Brabazon]

Hi,

Before you play around with the mixture adjustment screw.

On Weber's the mixture adjustment screw only really adjusts the
mixture on idle. If the engine is running rich under load then it is
the jets you need to look at.

Steve
http://brabazon.org/Quantum.aspx

[rab c]

http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=150508547829

On 24 Oct, 09:53, Mark Miles <taxim...@yahoo.co.uk> wrote:

> This seems to be the problem I am having with finding a diagram for the carb as
> it is an '86 model cvh so I am guessing that the carb is probably an aftermarket
> unit or grafted on from a later engine. The carb has twin barrels and the idle
> adjust screw is a thumbwheel type which is parallel to the ground. There is a
> Weber tag attached to the carb but it has not aged  well and is mostly
> unreadable. I would have expected the mixture screw to be in the area you point
> out but can see neither a screw nor anything resembling an appropriate orifice
> to contain one. If all else fails then I shall have to remove the carb, find the
> screw then refit it to set it up which seems a disproportionate amount of work
> for an engine that appears to be running well.
>
> Mark
>
> ________________________________

> From: "MichaelHughe...@aol.com" <MichaelHughe...@aol.com>

> To: quantu...@googlegroups.com
> Sent: Sun, 24 October, 2010 0:46:45
> Subject: Re: [Quantum Owners] mixture adjustment.
>

> In a message dated 24/10/2010 00:00:26 GMT Daylight Time, taxim...@yahoo.co.uk

> writes:
> I have a Weber carb on the car
> If it is 1987 or later the mixture screw should be to the left and a little
> below the idle speed screw.
> The idle speed screw is mounted at an angle - head downwards and has a coil
> spring acting as a locking device.  the mixture screw may be concealed behind a
> blocking plug so from the exterior it may just appear as a blanked off tube
> moulded as part of the carb body.  remove the plug to reveal the slotted screw
> head.
>
> The Haynes manual also notes that when adjusting the idle speed screw the
> electric fan should be kept running all the time.
>
> Michael--
> You received this message because you are subscribed to the Google Groups
> "Quantum Owners Group" group.
> To post to this group, send email to quantu...@googlegroups.com
> To unsubscribe from this group, send email to
> quantumowner...@googlegroups.com

> For more options, visit this group athttp://groups.google.com/group/quantumowners?hl=en

[rab c]

http://www.youtube.com/user/cloghoge?feature=mhum

On 24 Oct, 11:11, Mark Miles <taxim...@yahoo.co.uk> wrote:
> Having now looked at a blowup of the carb it would appear that the only
> adjustment is on the idle mixture. As the car appears to be running rich across
> the entire rev range I would assume that in order to sort the mixture I would be
> looking at re-jetting the carb or getting more air into the engine. I have the
> standard air box and filter on the car at the moment but I did notice that it
> appeared to be significantly leaner with the box off. Would it make that much
> difference if the carb had been jetted for use with some sort of induction kit?
> Personally I wouldn't have thought it would have made that much difference until
> you got into forced air solutions.
>
> Mark
>
> ________________________________

> For more options, visit this group athttp://groups.google.com/group/quantumowners?hl=en

>
> IMPORTANT NOTE: All information presented herewith is provided on an "As Is"
> basis, without warranty or the implication thereof. Neither the Quantum Owners
> Club nor the individuals associated with the Quantum Owners Club or in the
> preparation of the above information shall have any liability to any person or
> entity with respect to liability, loss, or damage caused or alleged to be caused
> directly or indirectly by the instructions contained within this or related

> message(s).- Hide quoted text -
>
> - Show quoted text -

[Jim Hearne]

I wonder if somebody has fitted a carb from a 1.6 engine ?

Jim

[Hamish Freeman]

When I was learning about carburetors some 45 years ago, the order of
preference when checking for faulty operation was as follows:
- If in doubt do not move anything whose use you do not understand - read
books and get skilled help: start on the outside and work your way in
- Locate your nearest stockist before undertaking any work - things can
break unexpectedly that worked perfectly well before!
- Fuel level in float chamber - too high gives rich mixture - check float is
actually "floating" and has not gone porous or holed if hollow (Common with
SU floats in the late 60's! - I had four in succession on a Spitfire in 1968
inside 6 months). For many years, Japanese carburetors had float chamber
windows to check that the fuel level was correct.
- Float valve not seating - the other part of high fuel level, normally
accompanied by a smell of petrol if the fuel is overflowing
- Fuel pressure too high - will overcome the float valve closing pressure.
Normally caused by use of the wrong supply pump or return line being
blocked. Many people fitted Filter King Regulators as both a filter and
pressure regulator to overcome such instances. Check if the pressure varies
with engine speed if the engine is fitted with a mechanical pump as faults
here could give a problem at high engine speed but be fine at idle
- Crud level in float chamber - any sign of crud in the bottom of the
chamber indicates that there will be more deposited in the jets so a good
blow through with an airline is most likely required, preferably with the
jets out - do not poke the jets with bits of wire or drills!
- Brown staining in the float chamber - this is most likely a stain/deposit
from the fuel and is probably so thin that it is insignificant and can
usually be removed with a dose of Redex or similar in the tank.
- Adjustment - on fixed jet carburetors the adjustment only operates at the
idle condition as it is usually a bypass control on the idle jet. On
variable orifice carburetors such as SU's, moving the main jet affects the
whole of the operating range
- If plugs come out black then there is an excess of HC in the mixture but
is it fuel or oil? Give the engine a run at high load, preferably up a hill
but not necessarily desperately fast then check the plugs as this overcomes
to some extent any influence of oil. If it is oil then you would notice a
high oil consumption if it is burning on the plugs and normally high blow
bye
- Wear in spindles that run in the carburetor normally cause a weak mixture
- Carburetors fitted with accelerator pumps could see a rich mixture if the
diaphragm has failed - pressure test if possible at a lowish pressure, not
an airline

I will see if I can drag some more from my memory but any Haynes manual for
a carbureted car has a good checklist

Good luck,

Hamish

----- Original Message -----
From: "taximark" <taxi...@yahoo.co.uk>
To: "Quantum Owners Group" <quantu...@googlegroups.com>

Sent: Saturday, October 23, 2010 10:21 AM
Subject: [Quantum Owners] mixture adjustment.