34 PICT 3 re-build advice please....

[Oldman]

Hi all, trying to get to the bottom of the (non) idle issue on my son's '71 DP 1600......stock Solex 34 PICT 3 .
Last weekend I pulled the carb., thoroughly cleaned it and put a kit through it hoping that it'd assist with idle.
It didn't. It starts first kick, runs on choke - no issue and drives beautifully.....but will not idle.

There are a couple of q's that I'd like input on, please......

1. There are two captive BB's in the body of the carb.
    I was reluctant to release/free these and left them as is. ie didn't clean them.
Do these have anything to do with the idle circuit ?

2. The Main jet and Idle jet did not have O-rings on them but have a shoulder that (to me) looks as though there should be O-rings in place.
    I put O-rings on both.
    Should I have ? - The Carby Kit did not have O-rings in it other than for the Idle /air adjustment screw ( the larger of the two).
    The replacement Mixture screw had an O -ring already on it.

I'm going to pull the carb down again tomorrow and check if I've missed anything, so any advice is greatly appreciated.

[Barry]

Mark

There is a good rebuild write up for the 34 Pict 3 on Rob and Dave

http://www.vw-resource.com/carb_41.html

[Oldman]

Thanks for that Barry…..great read.

So, based on the exploded diagram there aren’t O-rings on:
Main jet
Idle jet ( Pilot jet ), or
Air correction jet….
There is only reference to O-rings made on Mixture and Bypass screws.

mmmmm…….maybe I’ve overthought the need for O-rings and could be the issue ….
Good thing it’s a 5hitty, rainy day here……..good for pulling all down again!

Will post result………

[grumble]

Thanks for that Barry…..great read.

So, based on the exploded diagram there aren’t O-rings on:
Main jet
Idle jet ( Pilot jet ), or
Air correction jet….
There is only reference to O-rings made on Mixture and Bypass screws.

mmmmm…….maybe I’ve overthought the need for O-rings and could be the issue ….
Good thing it’s a 5hitty, rainy day here……..good for pulling all down again!

Will post result………


Mark the gasket on the main jet is just a fibre washer, the pilot jet seals on the taper& the other jets seal when they are tightened. The electrical connection to the pilot jet is often dodgy & the solenoid also open circuits. Assuming that the manifold gaskets and rubber boots are not leaking and there is no play in the throttle shaft.

[syncro]

You should be able to feel the solenoid click when you turn the ignition on.

[Oldman]

Sorry Gents, Type 1 1600 DP…..my son’s bus, Herman….no rubber elbows or fuel cutoff solenoid.
Big thank you to Barry for posting that link…..it certainly helped a lot.

Update…
Success….…
Pulled the carb off the bus this morning and stripped it back down.
(Gets quicker, the more you do it ……. )
Removed the redundant O rings and cleaned it all up again.
Also modified the top/bottom gasket as it wasn’t really a great fit, partially blocking galleries and offset on the securing screws…..much happier with the fit now.
I didn’t go down the BB route……. 
Reset the choke element to the factory marks on throttle body and choke element itself.

Spent 1/2 an hour chasing a 13 mm nut around the engine bay……..damn, having a top access hatch on my late bay saves time for this sort of stuff !
Carby reinstated I set the baseline on mixture and idle/air bypass……….and crossed thumbs.
Battery reconnected, turned the key and Herman kicked into life…..under choke.
Waited for the engine to warm up and…………it now holds idle off the choke cam !
Spent 10 min. or so fine adjusting mixture and idle and he’s purring nicely 

[Barry]

Give that man a beer!

[Barry]

Sorry Gents, Type 1 1600 DP…..my son’s bus, Herman….no rubber elbows or fuel cutoff solenoid.

Mark

The 34 PICT 3 does have a fuel shut off solenoid ……#16

[Oldman]

Mark

The 34 PICT 3 does have a fuel shut off solenoid ……#16

Listed as electromagnetic cut off valve….
Pretty sure that’s air cut off…….I’ve read elsewhere where folks clip the plunger off the end but keep it installed. 
From The Samba:
"The 34-Pict carbs do not have an electric cutoff attached to the pilot jet, as some earlier models did. Instead, it has a cutoff valve on the other side in the idle air bypass channel. It is essential for the car to start and idle that the valve is opened, as normally happens when it's energized by the ignition
circuit. 
If you put an appropriate plug/seal where the cutoff valve normally goes, the car would probably operate normally, but may tend to run-on in some
circumstances."

[syncro]

Listed as electromagnetic cut off valve….
Pretty sure that’s air cut off…….I’ve read elsewhere where folks clip the plunger off the end but keep it installed. 
From The Samba:
"The 34-Pict carbs do not have an electric cutoff attached to the pilot jet, as some earlier models did. Instead, it has a cutoff valve on the other side in the idle air bypass channel. It is essential for the car to start and idle that the valve is opened, as normally happens when it's energized by the ignition
circuit. 
If you put an appropriate plug/seal where the cutoff valve normally goes, the car would probably operate normally, but may tend to run-on in some
circumstances."

The solenoid shuts off the fuel to the idle circuit.