5 turns is ridiculous. is the o-ring on the mixture screw undamaged.

 

And 95 main jet is surely too small for 1.3 engine with 24mm primary venturi of a 32/34 DMTL

 

It won't be giving enough before the 45 slow-running jet runs out of flow..

Let me look up what other people used.

 

 

 

and see the FAQ thread

 

Cheers! I might just drop that 100 in quickly and see how it plays with that. Got time to fiddle with it all today, this would explain a lot of problems I suppose.

Edited 3 September, 20197 yr by anessen

Hopefully, idle/slow-running  can carry the engine to 3000ish usually. If you have somewhere quiet and nearby you could try a very short drive at low speedd with the primary main stack removed, and that will let you know at what revs  idle runs out of puff and main would cut in. F22 is quite aggressive emulsion. Is it definitely in primary side? F30 is smoother delivery I found.

 

Is the ignition timing correct?

Primary side would be on the right hand side as you're looking at the carb (from the front of the car), yeah?

So looking at the top of the carb:

[Primary Barrel w/choke flap]

[Sec. Idle] [Sec. Main] [Prim. Main] [Prim. Idle]

[Secondary Barrel]

 

I think the ignition is fine, I'll go over that again tomorrow. It's not been done for a while. The 100 primary main makes it feel better at the higher end but still getting misfiring at partial throttle below 3k.

Erm, 😕 i had a reverse mounted 30DMTR then a 32DMTL like yours, then a 34DMTR from a Lancia and now Dellortos.

 

Open the choke flap, follow the bridge from the inner venturi in that barrel to the jet holes. The jet holes pointed at by that bridge are primary. 

primary is fed by top two jets  in above pic. Outer (smaller - no hole) is idle jet.

 

(from a nova link - oh the shame)

 

If you remove both idle and main, always fit the main jet back first.

 

Edited 3 September, 20197 yr by dvderlm

What air filter are you using?

Have you modded exhaust?

 

If very free flowing it might need more than 45 idle.

 

Need to work out if is a lean or rich  misfire.

What colour are the sparkplugs?

Get a Gunson colortune?

Or borrow a gas analyser? 

 

I managed with 37.5 as standard in the original Pierburg 2e3 with 22/26 venturis for my GK as it is high compression

with long air filter feed. I'm not sure how the idle air corrector is sized for Pierburg.

 

40 idle worked in the 22/22 Weber 30DMTR, but is too weedy for most 32/34DMTL with 24/25 venturis. 45 is usually good. Some people need 50 and only 1 turn out on mixture.

Shame Weber don't do a 47.

Float height will affect the mixture too. Too much droop and it is lean.

 

Mine will just about wheeze along with 43 idle per barrel on the twin carbs with 31mm venturis like Lancia Fulvia, but many 1.3 need much more. Dellorto do steps of 0.1mm 

which is vital. On a Weber progressive you can use the mixture screw for fine adjustment of slow running. 

 

I got a Colortune, that thing's really cool!

I found a new (old) mixture screw from a rebuild kit. I also fiddled around, put a new vacuum line to the air box temperature switch, and blew carb cleaner through some of the air holes on the top of the carb.

 

Things are a lot, lot better now! The colortune shows idle at ok-leanish condition. Fiddling with the screw makes the idle stop rising about 2.5 turns out. Going on to throttle is quite sensitive, although I think there might be a little slack in the cable so will rule that out. The new jet I put in on the primary seems to make it run rich (yellow flame at higher RPM?). Will be fiddling about with this some more.

 

At the moment though, it pulls just fine with the choke in. My test was, can the car accelerate from 1.5k revs in third? Yes, it can. Plenty of torque (for a 1.3) to make the car move, no misfiring. As things are, it looks like a case of tuning rather than actual issues with the carburettor.

 

I'm guessing the mixture screw made the difference because that's the biggest thing I changed, this one feels a little spongy where the ring is meeting the inside. It actually feels like the one on the old Pierburg. I don't know how the different profile affects things, but, it seems to work. (The new one is on the left in the pic)

I'd have to look at another screw, to confirm, but O-ring closer to pointy tip is probably right.

 I can't remember what the taper is meant to be like. Smooth taper obviously linear. 

 

Looked at 32/34DMTL (from a Landrover I think and very crusty) it has stepped mixture screw.

A  30DMTR - (type 103/252) had the tapering screw.

 

Both had o-ring at slotted head end and not above the thread.

 

I suppose the tube is long enough to seal.

Might you have damaged the mixture screw tube with a slipped screwdriver tip?

Carb body is soft alu.

 

Removing the tapered one with fingernails (and old hardened maybe leaky o-ring) was easier than the other whose o-ring was still soft.

 

www.webcon.co.uk/shopexd.asp?id=5234

is stepped and correct for DMTL

 

But if the NOS one works, go with it.

 

 

On 07/09/2019 at 17:07, anessen said:

 The new jet I put in on the primary seems to make it run rich (yellow flame at higher RPM?). Will be fiddling about with this some more.

You probably need to be over 3000rpm with some load on engine but secondary not opening  for that 100 primary jet to be only one in action.

 

You are more likely to be seeing the accelerator pump enrichment producing yellow for a few seconds run with no load.

Always wondered about a tiny camera pointed at the Colortune plug....