Weber 34 ADM carb conversion info

[kennykoala]

have put a new kit in but she is cutting out when i have stop and at crossroad or stop sign,restarts but same at next corner, have a adusted idle miture in then 1  1/4 turns out but does not make any difference eithier in or out, to stop it from cutting out av put up revs but its running to fast,can you help please. kenny.

[MrEH]

Hey guys, I’ve fitted one in my EH

with heavily worked 186

it’s been rebuilt but seems to run rich!

1963 AP5 did you do the solenoid delete 

and what size larger idle jet primary mate?

On 24/03/2023 at 08:41, 1963 AP5 said:

Looks like the large jet holder is still available overseas

Primary Idle Jet Holder for Weber 32/36 DGAV, Large Size - Pegasus Auto Racing Supplies

52570.011 - Jet Holder LARGE fits Weber 32/36 DGEV DGV DGAV DFEV DGES (carburetion.com)

and Weber Performance in Australia still sell the larger jets to suit the 34ADM.

DGAV DGAS ADM Weber Carburettor Idle Jet (larger primary) Weber Performance Carburettors

Have a look down the carb barrels on a 34ADM, you will notice that even though both have 34mm butterflies the venturi sizes are very different between the primary and secondary. Insufficient air velocity through that big secondary venturi can be a problem on small engines unless they are fairly heavily modified and screaming. The carb is really designed for larger capacity engines (4.1L Falcon) but was a popular swap for modified engines with smaller displacement simply because they were cheap and plentiful back in the day. Mine works great on a 3.3L Holden 6. I have never tried one on anything smaller but I have heard of people having success with them on modified 4 cylinder engines.

Hi mate, did you do a large primary jet for your Holden 6? If so was it in your link

with Jet holder?

[1963 AP5]

Hi there, sorry it seems I haven't caught up on this thread for a while. I removed the 2-stage idle jet, and you used to be able to buy a larger jet holder from Weber Performance in Australia that would fit in its place but unfortunately, I don't think they are available anymore. I think the large jets are still available, but I think you would need to make a jet holder to suit. I used the standard primary and secondary jet, and it ran very well. Pay close attention to the power valve port and operation of the power valve as this is one of the reasons that these carbs run rich when installed on an adaptor plate. 

[MrEH]

hello, I’m wondering on a holden 6

do you need to change the secondary jet also?

[1963 AP5]

I ran the standard 210 secondary jet and the AFR was pretty good. 210 seems like a really big jet but the secondary venturi on a weber 34 is much larger than the primary so you may not get a large pressure drop in the venturi. I think that's why Ford used such a large jet to get the fuelling correct. I'd give it a go with the standard jet, and you can always play around with it later if you need to.