Vacuum Diaphragm - This is the rest of the vacuum unit mentioned at the front, as seen from the side. The vacuum operates a lever, that's about all I know about it to be honest.

The brass UFO is there to open a fully closed choke flap when the engine fires. The vacuum capsule is pulled on by air being sucked into the now running engine whose suction force changes from starter motor cranking speed (50rpm?) to fast idle speed (>1100rpm). A flat bar is pulled by a diaphragm towards that suction which connects to lever that acts on the bent rod which pokes up through the top half of the carb and acts on the choke flap through a spring. You pull the choke cable which closes the choke flap tight and when once running still the vacuum diaphragm opens the flap slightly. Unless its brass monkey cold you'll push the choke cable in to idle at ~1100rpm then drive off and push it fully home as the engine warms. Judging by the lack of spare parts vacuum capsules appear to last forever. The rubber pipe that connects it might perish though.

If you want to take the top half off the carb for access to accelerator pump jet, floats, needle valve etc. the capsule needs to be demounted (with the choke operating rod raised) - two short bolts and an easy to lose circlip and washer.

• On a DMTR the capsule bolts straddle upper and lower halves.
• On a DMTL the capsule bolts are both in the lower half, but the lever pivot point with the circlip is on the upper half.

I've not found it necessary to remove the rubber pipe when demounting the capsule in situ. This might help against premature splitting or the brass UFO falling beneath the car. On mine the pipe inlet is angled slightly.

Quick one,

Does anyone know the float height setting for a DMTL? I've stupidly messed mine up while taking the top cover off...

7mm, or parallel to the lid if you're in a rush!

Cheers

Hi all,

I've just bought a DMTL and a re-build kit for said carb. From everything I've read on this thread and others, to get the most out of this mod I ought to change my inlet manifold (engine is from '88, 1272cc, so I presume MH code) the popular choice seems to be the GK, but have heard mention that the '2G' is better. What cars were these fitted to, and how do I get my mitts on one? Also, is it wise to perform surgery on the 'hedgehog' heater to get things flowing better? One more question, the carb is apparently coming (hasn't arrived yet) with the correct adapter block, but I know I'm going to need to make arrangements for the throttle and choke linkages, and possibly the airbox too (?) what are the best (i.e. the easiest for an impatient oaf like me) solutions to these issues, in the experience of those that have done it? Car is an '88 coupé S btw.

Hi all,

I've just bought a DMTL and a re-build kit for said carb. From everything I've read on this thread and others, to get the most out of this mod I ought to change my inlet manifold (engine is from '88, 1272cc, so I presume MH code) the popular choice seems to be the GK, but have heard mention that the '2G' is better. What cars were these fitted to, and how do I get my mitts on one? Also, is it wise to perform surgery on the 'hedgehog' heater to get things flowing better? One more question, the carb is apparently coming (hasn't arrived yet) with the correct adapter block, but I know I'm going to need to make arrangements for the throttle and choke linkages, and possibly the airbox too (?) what are the best (i.e. the easiest for an impatient oaf like me) solutions to these issues, in the experience of those that have done it? Car is an '88 coupé S btw.

bump for this as i'm in the same boat

any info appreciated - especially on overcoming the throttle linkage as the my carb (presumably off a golf) has the linkages pulling from the front of the car not the rear

ta

mack

You can just rotate the carb to face the other way, although this may have it's own issues The info about inlet manifolds is covered in the other pinned weber thread.

is there any point in putting a weber carb in my 1ltr breadvan?

if it is a single choke 32TLA then yes, a twin choke will be a little unnecessary.

Today's topic is emulsion tubes:

Does anyone have any info on the various emulsion tubes that are available for these carbs? Having just missed out on a GT to use for parts to convert to injection I want to get my weber working as it should. I think my problem is my pump jet is too small (that's what she said!) but also I think the right emulsion tubes will help. The standard DMTR for the 1.3 has a 40 pump jet and F22 and F30 emulsion tubes and having seen some other emulsion tubes about the place I can draw up a list. Maybe if you have seen another one and have info on what sort of enrichment it provides we can have some sort of database of what's hot and what's not.

So here's the list

F22 Standard Primary EM tube for the 1.3 polo/golf. Richens mixture at low engine speeds to offset small pump jet size.

F25 Standard Primary EM tube for the 1.6 golf/scirocco. I don't know about this one but I suspect similar to F22 as it looks quite similar

F30 Standard Secondary EM tube for most of the weber DMTR/Ls I've seen. Bit of a "Jack of all Trades?" I found it worked well on both my DMTR and DMTL in the primary stage and gives better economy than the F22 but at the expense of performance (unless you fit a bigger pump jet perhaps?)

F33 Secondary EM tube on 1.8 golf/scirocco. I don't know much about this one: any comments?

Anyone got a good economy jet set up for a Mk2 with a DTML?

This is a 2G engine by the way, 55bhp all stock.

It comes with 100 Primary and 115 Secondary jets or 95 Primary and 120 Secondary.

Whats the pipe for drectly behind the inlet thats points to the right?

Is it actually used and also on a Mk2 Polo as you look in the bay, on the bulkhead to the right of centre there a small black bok with two vac pipe nipples on, ones pink and ones green. Whats this for and is it needed on a weber conversion if i put the vac advanceto the lower vac nipple on the carb? presumably i would block off the inlet manifold vac take off

cheers Will

Today's topic is emulsion tubes:

Does anyone have any info on the various emulsion tubes that are available for these carbs? Having just missed out on a GT to use for parts to convert to injection I want to get my weber working as it should. I think my problem is my pump jet is too small (that's what she said!) but also I think the right emulsion tubes will help. The standard DMTR for the 1.3 has a 40 pump jet and F22 and F30 emulsion tubes and having seen some other emulsion tubes about the place I can draw up a list. Maybe if you have seen another one and have info on what sort of enrichment it provides we can have some sort of database of what's hot and what's not.

So here's the list

F22 Standard Primary EM tube for the 1.3 polo/golf. Richens mixture at low engine speeds to offset small pump jet size.

F25 Standard Primary EM tube for the 1.6 golf/scirocco. I don't know about this one but I suspect similar to F22 as it looks quite similar

F30 Standard Secondary EM tube for most of the weber DMTR/Ls I've seen. Bit of a "Jack of all Trades?" I found it worked well on both my DMTR and DMTL in the primary stage and gives better economy than the F22 but at the expense of performance (unless you fit a bigger pump jet perhaps?)

F33 Secondary EM tube on 1.8 golf/scirocco. I don't know much about this one: any comments?

Theoretically a carburetor should accelerate without the pump jets, they're only there to stabilise the mix when a quick depression of the pedal is made. The right emulsion tube will allow the right progression of fuel throughout the rev range (or thereabouts). The F22 sounds like it leans off towards the high end as the fuel in the well reduces.

The diameter and position of holes is crucial in emulsion tubes, as is the diameter of the emulsion tube itself. The thicker the emulsion tube the leaner it tends to be as less fuel can sit in the well around it.

which webber do you guys recomend for a 1.04l 1990 polo fox, standard hz engine. its got a peirburg on there at the moment, with the common auto choke problem.

just got hold of a webber, hopefully arriving soon. will i need an adapter plate or new inlet manifold, or will it bolt straight on?

do you know what youve purcahsed ? weber make alot of carbs lol

do you know what youve purcahsed ? weber make alot of carbs lol

i dont know the modle, I'm waiting for matey to get back to me with it. it was taken from a H reg 1.04l parade

The return thats blockoed off in yellow, can you just change the blank for a return or do you have to run a swirl pot?

I'm looking to get a weber but i dont know if this one that i have found is right for my engine.

my car is a mk2 bready ranger 1.3 5spd.

the spec that i have been given for the carb is:

The Weber designation is : 34 DMTR 21 / 200.

they said it came from a vw.

could someone tell me if this will be ok for my car:)

I bought one and fitted it today but I am suffering from teething problems namely it won't start without choke and full throttle

Has anybody got a diagram of the DMTL? I need to know where the mixture screw is.

Hi there,

Putting a DMTL on my 1272 s engine. Anyone have any idea what size jets id need?

thanks.

Hi there,

Putting a DMTL on my 1272 s engine. Anyone have any idea what size jets id need?

thanks.

At the moment I'm running

IDLE: 45 65

MAIN: 115 120

EMULSION TUBE: F30 F30

AIR JETS: 190 180

Thats with a 268* 268* newman camshaft, webber DMTL , ported + polished cylinder head.

Still think I'm running lean on the second stage however.

Not sure if anyone can help.

Just got a DMTL and pretty happy with it but there seems to be an issue with pulling away under part throttle. When trying t pull away normally, the car starts going then stalls. I'm guessing this is the carb changing over from the idle jet to a first stage or something? I'm not very clued up of carbs. My friend said it may have something to do with the accelerator pump or its jet or something? But i had a look and the pump itself doesnt seems adjustable and I'm not sure what jet controls this? Could this jet be the wrong size so the car is over/under fueling as its pulling away?

Any help would be great!

Thanks.

Alright mate,

Going on the idea that the carb is in a serviceable condition, and there is no air leaks, it sounds like a lean stumble. Does it become worse the greater the load?