russbost
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| posted on 30/4/24 at 02:18 PM |
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Pinto Twin Choke Weber problems
Hi all, hoping someone can throw some light on this for me - 2.0 Pinto installation in my NG, car didn't run when I got it & had obviously
been considerably messed with in the past, timing belt was a tooth out, reset points (remember those?!) timing, tappets, etc. put some fresh fuel in
& dropped some down the carb &hey presto, it ran, however, had very obvious carb probs, I whipped the carb off & stripped cleaned, blew
out all jets, checked diaphragms for splits etc & reassembled, it runs better, but still nowhere near right.
Even when completely warm the choke flaps at idle are as pictured below, only slightly open,
[img]
 
Carb Chokes
[/img]
as soon as the throttle is opened the choke flaps also pull open fine & at revs, it runs perfectly, at idle, it hunts & I'm unable to
significantly affect it with the idle screw. The really odd thing is that, despite the chokes being a lot further closed than you'd expect it is
clearly running weak at idle, if I partially cover the chokes with my hand, blocking the air supply, the idle picks up & it runs much more evenly.
The float level had been set waay high, presumably cos someone had worked out it was running weak, that's been reset to standard, didn't
make any noticeable difference
I'm currently going through the procedure for resetting the vacuum pull down for the choke, the choke phasing & the fast idle, but I'm
sure that's not going to sort it-
I've noticed when looking at the vac pull down that I think there's an issue that the linkage may be bent - see pic below
[img]
 
Carb choke
[/img]
Surely the little arm should be behind the yellow "plug" so that the yellow bit pushes it along when the vac diaphragm pulls it? I still
don't think that's enough to hold the chokes so far closed & what could be wrong at idle that it runs so weak?
I can't find a schematic for the carb, but I'm pretty sure the idle screw only controls an air passage & even with the screw right in
it's still running weak, exactly which jet is it pulling fuel from at idle? I don't think it was clear in the manual, tho' I'll
take another look.
The auto choke spring feels like it's wound on way too tight, but there's no mention of adjustment for that part of the choke anywhere I can
find. It looks as though the 2 halves of the choke housing should separate, but the bolt appears to be seized in the housing, if I can get it free, I
might be able to slack the choke off, but that's just gonna make the idle even worse!
I don't suppose anyone has a decent Cortina/Sierra twin choke they no longer want or a set of bike carbs suitable for conversion for reasonable
money? This has got me tearing my hair out - I used to make my living 30 years ago fixing exactly this sort of stuff, but don'rt ever recall
coming across anything quite like this b4!!!
I no longer run Furore Products or Furore Cars Ltd, but would still highly recommend them for Acewell dashes, projector headlights, dominator
headlights, indicators, mirrors etc, best prices in the UK! Take a look at http://www.furoreproducts.co.uk/ or find more parts on Ebay, user names
furoreltd & furoreproducts, discounts available for LCB users.
Don't forget Stainless Steel Braided brake hoses, made to your exact requirements in any of around 16 colours.
http://shop.ebay.co.uk/furoreproducts/m.html?_dmd=1&_ipg=50&_sop=12&_rdc=1
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NOTE:This user is registered as a LocostBuilders trader and may offer commercial services to other users
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gremlin1234
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| posted on 30/4/24 at 02:50 PM |
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I am no expert on these, but it does sound like a classic [manifold] air leak problem.
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nick205
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| posted on 30/4/24 at 04:08 PM |
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I fitted a 2.0 pinto with manual choke Weber carb like that in my MK Indy. It wasn't the carb the engine came with in the donor Sierra. Engine
started and ran, but just wouldn't go through the revs above 3,500. Also stalled very easily. Having it rejetted on a rolling road by a local
expert Airey Tuning made a world of difference. Opeed up the full rev range and stopped the stalling.
Your problem does seem air leak related + you've already had it apart and serviced/cleaned it.
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Dingz
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| posted on 30/4/24 at 05:13 PM |
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The autochoke is held in position by a circular clamp ring with 3? Fixings, when its hot slacken them off rotate the housing til the choke flaps open
fully. Are you sure you have cleaned the idle jets thoroughly, there should be 2 one for each choke and when you remove them give a good blast of carb
cleaner down the drillings.
Phoned the local ramblers club today, but the bloke who answered just
went on and on.
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russbost
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| posted on 30/4/24 at 05:59 PM |
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quote:
Originally posted by gremlin1234
I am no expert on these, but it does sound like a classic [manifold] air leak problem.
Deffo not an air leak, have been all over it with a stethoscope, clamped off vac hoses to distributor, servo & breather. Breather made slight
difference, others none at all, you'd expect the breather to make some difference .....
I no longer run Furore Products or Furore Cars Ltd, but would still highly recommend them for Acewell dashes, projector headlights, dominator
headlights, indicators, mirrors etc, best prices in the UK! Take a look at http://www.furoreproducts.co.uk/ or find more parts on Ebay, user names
furoreltd & furoreproducts, discounts available for LCB users.
Don't forget Stainless Steel Braided brake hoses, made to your exact requirements in any of around 16 colours.
http://shop.ebay.co.uk/furoreproducts/m.html?_dmd=1&_ipg=50&_sop=12&_rdc=1
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NOTE:This user is registered as a LocostBuilders trader and may offer commercial services to other users
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russbost
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| posted on 30/4/24 at 06:01 PM |
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quote:
Originally posted by Dingz
The autochoke is held in position by a circular clamp ring with 3? Fixings, when its hot slacken them off rotate the housing til the choke flaps open
fully. Are you sure you have cleaned the idle jets thoroughly, there should be 2 one for each choke and when you remove them give a good blast of carb
cleaner down the drillings.
Can't rotate the choke housing as it can only move slightly B4 the water hoses hit the rocker cover.
Must admit haven't specifically targeted the idle jets with carb cleaner, but they appear clean & have blasted through with compressed air
.....
I no longer run Furore Products or Furore Cars Ltd, but would still highly recommend them for Acewell dashes, projector headlights, dominator
headlights, indicators, mirrors etc, best prices in the UK! Take a look at http://www.furoreproducts.co.uk/ or find more parts on Ebay, user names
furoreltd & furoreproducts, discounts available for LCB users.
Don't forget Stainless Steel Braided brake hoses, made to your exact requirements in any of around 16 colours.
http://shop.ebay.co.uk/furoreproducts/m.html?_dmd=1&_ipg=50&_sop=12&_rdc=1
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NOTE:This user is registered as a LocostBuilders trader and may offer commercial services to other users
|
nick205
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| posted on 1/5/24 at 09:05 AM |
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quote:
Originally posted by russbost
quote:
Originally posted by Dingz
The autochoke is held in position by a circular clamp ring with 3? Fixings, when its hot slacken them off rotate the housing til the choke flaps open
fully. Are you sure you have cleaned the idle jets thoroughly, there should be 2 one for each choke and when you remove them give a good blast of carb
cleaner down the drillings.
Can't rotate the choke housing as it can only move slightly B4 the water hoses hit the rocker cover.
Must admit haven't specifically targeted the idle jets with carb cleaner, but they appear clean & have blasted through with compressed air
.....
Give them a proper good soaking in carb cleaner and ensure ANY claggy old fuel deposits are properly dissolved away. You mentioned putting fresh fuel
in the vehicle. There may well be chance the old fuel went nasty sat in the jets.
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SteveWalker
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| posted on 1/5/24 at 10:50 AM |
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I'll second that. My pinto engine (38 DGMS carb) wouldn't even attempt to start. Adding fresh fuel did not help, until I'd drawn off
around 20 litres of fuel (it came out looking like milk at first). Even then it was not running right, so I completely drained the tank and pipework
and refilled with fresh fuel. It is now running beautifully.
I also had a similar problem with a Matiz that has sat for a number of years. Again emptying and refilling quickly solved the problem.
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adithorp
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| posted on 1/5/24 at 06:55 PM |
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Thinking waaaay back, I seem to remember a common issue, that I think was caused by the bi-metal coil inside the thermo housing becoming loose on its
central fixing.
Remove the three screws and pull it back on the hoses. Memory says you could work out where it had originally been located from the original fixative
(flat on the shaft?). We stuck them back using loktite bearing fix (603?). As long as its close to original position you can then adjust by twisting
the housing.
Memory isn't what it used to be so could be talking nutsack 
"A witty saying proves nothing" Voltaire
http://jpsc.org.uk/forum/
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russbost
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| posted on 4/5/24 at 08:11 AM |
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quote:
Originally posted by adithorp
Thinking waaaay back, I seem to remember a common issue, that I think was caused by the bi-metal coil inside the thermo housing becoming loose on its
central fixing.
Remove the three screws and pull it back on the hoses. Memory says you could work out where it had originally been located from the original fixative
(flat on the shaft?). We stuck them back using loktite bearing fix (603?). As long as its close to original position you can then adjust by twisting
the housing.
Memory isn't what it used to be so could be talking nutsack
You've got me wondering now, whether it could be 180 degrees out, because that would fit the feel of correct preload, I'd not thought of the
spring coming off & being put on 180 deg further round, I'll check & see if it will come off.
Still leaves the issue of exactly how that vac pull down works, really need to see an unmolested one!
I no longer run Furore Products or Furore Cars Ltd, but would still highly recommend them for Acewell dashes, projector headlights, dominator
headlights, indicators, mirrors etc, best prices in the UK! Take a look at http://www.furoreproducts.co.uk/ or find more parts on Ebay, user names
furoreltd & furoreproducts, discounts available for LCB users.
Don't forget Stainless Steel Braided brake hoses, made to your exact requirements in any of around 16 colours.
http://shop.ebay.co.uk/furoreproducts/m.html?_dmd=1&_ipg=50&_sop=12&_rdc=1
|
NOTE:This user is registered as a LocostBuilders trader and may offer commercial services to other users
|
