A

andyboy66

New Member
Hi everyone.

I’m having some problems with a Weber 34ICH carb on my Series 3. I’ll try my best to describe it.

The basic problem is it won’t idle, so when driving I pull up to a junction dip the clutch and the engine cuts out.

I have tried setting it up as per the Weber instructions, starting with mixture screw, then the idle speed screw. I also pulled out the idle jet and blew it out. This resulted in a perfect drive. Pulled with power, idled perfectly, no sign of any hesitance. I’ll call this a “good” set up. It ran fine like this for a couple of days.

Two days later, jump in the vehicle, fire her up, drive on choke until fully warmed up. When the choke was pushed in the vehicle won’t idle. It dies and is nowhere near the idle I had two days ago.

Also, I notice that under very slight throttle – just tickling the throttle to keep the car moving – the engine is lumpy and erratic – it kind of hunts up and down in revs, the exhaust note sounds uneven and it feels like the carburation is all wrong again. If the throttle is pushed on past this rough spot to higher RPM’s it smoothes out and pulls fine. It didn’t do this on the day when I had the “good” set up.

I would have a go at just adjusting the idle screw again until it doesn’t cut out. But that has it ticking over too fast just to stop it cutting out at junctions. And then I know I’ll jump in one day and it will be running again like the “good” set up I described above and then the idle speed will be way too fast. And actually it doesn’t remedy the underlying fault.

The engine is sweet as a nut on a good day and the car is a pleasure to drive. But it’s a complete pig when it’s playing up. It appears to be an intermittent issue that is changing carb’ set up but I have no idea what is changing between a “good” day and a bad day.

Does anyone have any suggestions for what to look at next beyond the set up procedure I’ve already done please?

Cheers

Andy
 
I would think you have dirt in the carb and it'll need a full strip down, also get an aerosol of carb or brake cleaner.
 
Had very simular prob with my series, ended up air leak. Get some carb cleaner and with engine running spray around the carb, this should hopefuly help pinpoint the leak.
Mine had 2 one was carb insulater the other wad the accelerater jet diaphragm. Hope this helps.
 
I had similar problems with the old weber, after taking the manifolds off and fitting new gaskets all round the problem was improved however it was still leaking round the butterfly pin... Does sound like air is getting in to me rather than much but it is still worth getting a rebuild kit and stripping down.
 
Have you blown out the vacuum pipe and checked that the advance/retard mechanism in the distributor is working freely?
 
Hi everyone, I'm a newbie with the same problem although it is constant, not intermittent! I tried the carb cleaner spray but with engine off, will try again with her running as it had no effect.
A mate suggested I check the sedimenter for gloop... Is it possible to remove the glass bowl part without taking out the whole unit??
Thanks in advance...
 
Just a quick update...
Changed plugs... No effect
Sprayed carb cleaner with engine running... No effect
I did find a piece of wood about the size of a cigarette jammed into a nozzle on the carb, beside the idle adjustment. It was charred and brittle so I'm guessing had been there a while? Air was being sucked into the carb through this nozzle which was restricted by the piece of wood.
There was no hose that seemed to connect this nozzle so I removed it, cleaned it and plugged it with a rawl plug and screw.
Result: Engine now purring like kitten and idling so quietly I can barely here it in the drivers seat...!
Not sure what I did exactly, other than update the previous bodge but it worked :)
 
Not sure why there would be a blocked jet, but if she works leave it. Glad your up and running again mate, enjoy
 
dominicbeesley said:
Take us a picture of where this hole was and we'll tell you what it is supposed to do :)

D
Click to expand...
... Nobbidick, You're in Hebden Bridge and you need pictures to show you where a hole is!! (Dueling Banjos playing in the background) ;);)

Now you know why I left there!! :D:D

Jailape, you will probably find that there should be a bit of pipe that goes from there to the distributor!!
 
Last edited:
Nah, a picture of where it was....much more informative...

Is it vac advance pipe, or as I suspect, given the bit of wood was cigarette sized, the oil breather...
 
I'm no expert by the way, but..........

You can take a carb apart and clean it quite easily. Just make sure you don't blow compressed air through it over 30psi and watch you don't lose any parts blowing things out! Carb cleaner will do most of the work. Take pictures of each stage so you can put it back together. Download an exploded diagram of the carb from Weber or similar to help the rebuild.

Its worth putting a rebuild kit on too just while you have it all apart.

With my idle problem I just bought a second-hand carb for £35 which worked perfect. Keep an eye on ebay or similar as a rebuild kit can be best part of £20 from some sources.

I read somewhere that Webers can be prone to blocking up if you don't fit an inline filter so that would be an idea after any rebuild. Some people like to soak a carb in a special carb cleaning solution overnight. Good idea I reckon, just make sure you rebuild it with a kit after this as some non-metal parts could potentially perish in some cleaning solvents, just to be safe.
 
andyboy66 said:
Hi everyone.

I’m having some problems with a Weber 34ICH carb on my Series 3. I’ll try my best to describe it.

The basic problem is it won’t idle, so when driving I pull up to a junction dip the clutch and the engine cuts out.

I have tried setting it up as per the Weber instructions, starting with mixture screw, then the idle speed screw. I also pulled out the idle jet and blew it out. This resulted in a perfect drive. Pulled with power, idled perfectly, no sign of any hesitance. I’ll call this a “good” set up. It ran fine like this for a couple of days.

Two days later, jump in the vehicle, fire her up, drive on choke until fully warmed up. When the choke was pushed in the vehicle won’t idle. It dies and is nowhere near the idle I had two days ago.

Also, I notice that under very slight throttle – just tickling the throttle to keep the car moving – the engine is lumpy and erratic – it kind of hunts up and down in revs, the exhaust note sounds uneven and it feels like the carburation is all wrong again. If the throttle is pushed on past this rough spot to higher RPM’s it smoothes out and pulls fine. It didn’t do this on the day when I had the “good” set up.

I would have a go at just adjusting the idle screw again until it doesn’t cut out. But that has it ticking over too fast just to stop it cutting out at junctions. And then I know I’ll jump in one day and it will be running again like the “good” set up I described above and then the idle speed will be way too fast. And actually it doesn’t remedy the underlying fault.

The engine is sweet as a nut on a good day and the car is a pleasure to drive. But it’s a complete pig when it’s playing up. It appears to be an intermittent issue that is changing carb’ set up but I have no idea what is changing between a “good” day and a bad day.

Does anyone have any suggestions for what to look at next beyond the set up procedure I’ve already done please?

Cheers

Andy
Click to expand...
 
I got same Problem I've changed the carb And Manifold gasket still the same. andy did u sort it or anyone got any answers thanks lizard
 
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