Weber ICT issues, possibly

[callyspoy]

Hi folks,

My van is giving me a bit of aggro, annoyingly.
Basics...
2.0 A/C, stock, compression is good (new pistons/barrels last year, compression checked today)
I fitted some used weber ICT's about a month ago, after the van came with a single twin weber and i wanted to get twins on it.
It ran beautifully when i installed them. Like really good.
I went through the wayoutwestie set up guide, so fitted new 1.5 needle valves and the jets he suggested (they had f5 emulsions, so i left those as they are commonly used anyhow).
So yeah, straight away after fitting, it felt great. Low speed, high speed, exactly what people say ICT's are like, not exceptional, but really good solid carbs.

Anyway, a couple of days ago it began to pop and was struggling at slow speeds, misfiring etc.
I have gone through my spares on the ignition side- leads, plugs, cap, rotor even an alternative dizzy as a last resort.
I did always think it could be carb linked, as the most obvious thing, but thought i'd give the ignition side a go.
Anyway, the carb on 1-2 side (rhs as you look in the engine bay) appears to be the one causing drama. My exhaust is the cheapo empi one that has two separate pipes, and the popping is coming out of that side.
With filters off you can see it popping through there if you hold the throttle open slightly.

If you deck the pedal, it runs absolutely fine. Just the idle circuit appears to be causing an issue.(or is being masked when on mains).

So today i whipped the carb off and stripped it all down (i had done this prior to installing also) as assumed there could be some crap in the idle circuit on that carb. It was still clean, i couldn't see anything with a blast of carb cleaner in the ports to see if it dislodged anything. Looked generally clean inside still.
Fuel pressure was checked today, still at around the required 2.1psi, using a malpassi reg and facet elec pump.
I used my snail air reader to make sure they butterflies are synced, which they are. Linkage (hex bar) was adjusted several times with having removed the different components!

So, what next?
Things i haven't changed on the carbs is an overhaul kit, so no new gaskets, float or pump diaphragm. As mentioned, needle valve was replaced and the floats appear to be working as they should. They are brass and don't have any fuel in them. I swapped the pump diaphragm from one carb to the other also, just to check. No change.

Anybody have any pointers or ideas of what to do? I am loathe to just throw cash at the van on things it won't need. I wondered about the ignition amplifier, but i do think it is carb based.
Do i just buy the refurb kit, it would give me the gasket, float and diaphragm, i am just concerned that those items do not appear to be causing an issue and it is a fair wodge of cash.
What other things are there.
I can't see it being spindle wear as it ran absolutely fine up to a couple of days ago and setting the idle is easy.

Bit of an essay, but i am just a bit disheartened. I'd taken yesterday and today off work to work on the van getting the camper conversion built, but have lost both days to this running issue.
Any pointers appreciated.
Cheers
Callum

[davidoft1]

have you checked the float level is within spec? is it a green westy?

[callyspoy]

Hi David,
It is not a green westie, it's a yellow danbury. could be on fire soon if it doesn't start behaving!

Yes float was set when i installed, rechecked today and still at the same setting for both carbs and at the height suggested on wayoutwestie.

As an addition, since posting i have swapped the carbs around as they aren't handed (i don't know why it took mw so long to think to do that) it is now coughing on the LH bank (3-4). So rules out exhaust leaks, inlet manifold to cylinder head gaskets and ignition faults.
I'll strip the carb down again and have a proper dig around. Maybe this evening.

[davidoft1]

Hi David,
It is not a green westie, it's a yellow danbury. could be on fire soon if it doesn't start behaving!

Yes float was set when i installed, rechecked today and still at the same setting for both carbs and at the height suggested on wayoutwestie.

As an addition, since posting i have swapped the carbs around as they aren't handed (i don't know why it took mw so long to think to do that) it is now coughing on the LH bank (3-4). So rules out exhaust leaks, inlet manifold to cylinder head gaskets and ignition faults.
I'll strip the carb down again and have a proper dig around. Maybe this evening.

If you empty the float chamber and run it until it fills does it pop immediately ?

Can you see fuel running until the throttle body whilst it’s running?

[silverbullet]

Air leak? That would make it go lean under high vacuum conditions and make it misfire.

[callyspoy]

Hi folks,
Just a quick follow up.
I took the troublesome carb back apart. Didn't do much else to it other than the previous clean ups, but it does appear to have cured the fault.
It drives again as it did before this little episode. So that is good.
I can only assume some crud got in from the used malpassi reg i installed, as that is after the fuel filter.
Thanks for the help!