Issue with Butterfly Valve on 32/36 DGAV Carb.

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EightyFive
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Issue with Butterfly Valve on 32/36 DGAV Carb.

Postby EightyFive » Mon May 08, 2017 8:36 pm

Hi,

I seem to have a problem with my carb: I noticed that there was no 'spring back' on the butterfly valves, they would simply remain open. The only way I could get them to snap shut by themselves was to rotate the choke housing a 180 degrees, but even then it seems quite 'loose'. if I rotate the housing a full 360 degrees then it feels way too stiff. I have read to leave the center bolt alone as it easily shears, but at the moment can't see any other way to align the choke unless I am missing something?

Bear in mind I'm a complete amatuer and have never rebuilt a carb before, so please explain what I need to do like I'm 5!

Mc Tool
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Re: Issue with Butterfly Valve on 32/36 DGAV Carb.

Postby Mc Tool » Mon May 08, 2017 9:56 pm

Sounds to me like your fiddling with the choke flap not the actual throttle butterflies , and they don't have much of a spring at all , they rely on the bimetal in the choke housing ( the one you have just finished moving all over the place :xd: ) to control that choke flap. You really need to get access to a manual and suss out just how the auto choke and fast idle set-ups work and how they are adjusted ( specially now :xd: :D :D ) The throttle butterflies are further down the carb , you can see the shafts about 1/2 above the base of the carb :)
I have the patience of a saint ........Saint cnuty Mc Fuckoff

EightyFive
Posts: 139
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Re: Issue with Butterfly Valve on 32/36 DGAV Carb.

Postby EightyFive » Mon May 08, 2017 10:33 pm

Mc Tool wrote:Sounds to me like your fiddling with the choke flap not the actual throttle butterflies , and they don't have much of a spring at all , they rely on the bimetal in the choke housing ( the one you have just finished moving all over the place :xd: ) to control that choke flap. You really need to get access to a manual and suss out just how the auto choke and fast idle set-ups work and how they are adjusted ( specially now :xd: :D :D ) The throttle butterflies are further down the carb , you can see the shafts about 1/2 above the base of the carb :)


Hmm, just from all the videos I'd seen every time they'd adjust the choke housing they'd check the choke flaps. I've taken the carb apart (while reading the manual) and it's already given me a much better idea of how it all works. That's put my mind to ease somewhat anyway, looks like I should just focusing on rebuilding it and take it from there. (This is a spare carb btw so thought I might as well just get stuck in)

Mc Tool
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Re: Issue with Butterfly Valve on 32/36 DGAV Carb.

Postby Mc Tool » Mon May 08, 2017 11:50 pm

Having a go is the best way to learn . The auto choke receives a bit of bad press but if it is set up properly they work just fine , probly the only real complaint I have is that it holds the choke in operation for to long , for me I start the car and every direction from home is at least 10km before there is anything to stop for ..... so really once I am up to open road speed I don't really need the choke so much , not like if you had to negotiate peak traffic bumper to bumper stop and go driving straight away. One thing to watch for is throttle shaft bush wear on older carbs which can cause issues if its real bad ...... but they can be fixed :)
I have the patience of a saint ........Saint cnuty Mc Fuckoff

EightyFive
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Re: Issue with Butterfly Valve on 32/36 DGAV Carb.

Postby EightyFive » Tue May 09, 2017 10:41 am

Mc Tool wrote:Having a go is the best way to learn . The auto choke receives a bit of bad press but if it is set up properly they work just fine , probly the only real complaint I have is that it holds the choke in operation for to long , for me I start the car and every direction from home is at least 10km before there is anything to stop for ..... so really once I am up to open road speed I don't really need the choke so much , not like if you had to negotiate peak traffic bumper to bumper stop and go driving straight away. One thing to watch for is throttle shaft bush wear on older carbs which can cause issues if its real bad ...... but they can be fixed :)


I agree, always best to get stuck in.

Just to go back to the choke flaps, everything I am seeing online suggests the choke flaps should be closed while the carb is stone cold, if so this is what I'm having issue with. The only way I can get them to stay closed is if I put the choke housing at a funny angle.

Either way I can't do anything about it at the moment as the carb is in bits. I suppose I should just put it back together as best as possible and take it from there. The throttle valves at the bottom seemed to operate okay.

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pbar
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Re: Issue with Butterfly Valve on 32/36 DGAV Carb.

Postby pbar » Tue May 09, 2017 11:20 am

EightyFive wrote:
Just to go back to the choke flaps, everything I am seeing online suggests the choke flaps should be closed while the carb is stone cold


They need to be yes, that's correct. And it is the bi-metallic spring/strip in the housing which makes it so. The choke flaps gradually open as the car warms up (again due to the bi-metallic strip), until they become fully open when the car is up to temp. After your day of driving they will then remain this way, until the morning after when you press the accelerator before starting the car, the choke flaps should then snap shut. And the procedure begins again.

It's really ingenious. The guys making this stuff at Ford (or wherever else) were brilliant.

EightyFive
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Re: Issue with Butterfly Valve on 32/36 DGAV Carb.

Postby EightyFive » Tue May 09, 2017 12:03 pm

pbar wrote:
EightyFive wrote:
Just to go back to the choke flaps, everything I am seeing online suggests the choke flaps should be closed while the carb is stone cold


They need to be yes, that's correct. And it is the bi-metallic spring/strip in the housing which makes it so. The choke flaps gradually open as the car warms up (again due to the bi-metallic strip), until they become fully open when the car is up to temp. After your day of driving they will then remain this way, until the morning after when you press the accelerator before starting the car, the choke flaps should then snap shut. And the procedure begins again.

It's really ingenious. The guys making this stuff at Ford (or wherever else) were brilliant.


Is it possible then that as the car has been sitting, the choke flaps became stuck in the open position? Maybe this is why they aren't closed by default.

As I say though, the only way I have found to sort this out is to angle the housing at a funny angle, but this seems wrong.

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pbar
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Re: Issue with Butterfly Valve on 32/36 DGAV Carb.

Postby pbar » Tue May 09, 2017 12:19 pm

EightyFive wrote:
Is it possible then that as the car has been sitting, the choke flaps became stuck in the open position? Maybe this is why they aren't closed by default.


It would be possible I guess, a choke sticking is not uncommon. The choke flaps won't just close by themselves though, no matter how cold it is, until the accelerator is depressed (or similarly the throttle is pulled in the engine bay, etc.) The choke housing has marks on it to align it. It can be adjusted a small amount either way to make it more or less keen, it is just a small adjustment though, nothing like what you have described.

Mc Tool
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Re: Issue with Butterfly Valve on 32/36 DGAV Carb.

Postby Mc Tool » Tue May 09, 2017 9:46 pm

The choke flap will be 80 - 90% open when cold until you press the accelerator pedal then they snap shut and then open progressively as the engine coolant warms up . When you get in the car ... cold engine , you should press accelerator pedal ( most of the way) to the floor before starting . This sets the fast idle and the choke and the pedal press also give a shot of juice via the accelerator pump . I just been out to the car to verify this before I posted , I did as above and ( -4 deg frost here ) and it started within about 2 turns of the motor and settled into a 1000rpm idle
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Bug
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Re: Issue with Butterfly Valve on 32/36 DGAV Carb.

Postby Bug » Wed May 10, 2017 5:09 pm

Hi EightyFive,
Long shot I know, but if you happened to be anywhere near West Norfolk I'd happily help you with your carb set up.
As Major Tom has said,there is nothing wrong with an auto-choke if you know how to set it up correctly
I always kept mine and have fettled many over the years

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Re: Issue with Butterfly Valve on 32/36 DGAV Carb.

Postby Not_Anumber » Wed May 10, 2017 5:19 pm

If in doubt you could just get a manual choke conversion kit. Ive fitted these to a 32/36 and a 38/38 on Pinto engines and was pleased with the extra control it gave.

As you may be aware there is a position beneath the Capri dash (on the slanting bit) to fit a manual choke control, its currently covered by a round/ wedge shaped blank.


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