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Solex 30 pict 2 adjustment

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28K views 14 replies 5 participants last post by  tmea  
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#1 · (Edited)
Solex 30 pict 2 fuel metering screw

Right, i did dig around, asked uncle Google many times in different way and still did not find an answer to this:
I managed to unscrew fuel metering screw - yes, this tiny little bastard hidden next to accelerator pump - as my beetle was REALLY struggling to idle properly despite using all magic on it it was usually dying on idle when warm. Cleaned all passages, new brass bushes, gaskets changed and now I have one "little" dillema" - what is proper fuel metering screw setting? I know VW was pre seting them at factory and cover them with some crap, thats why so many of them finished at junkyard - not many people could clean and unscrew this spawn of Satan to clean idle passages.
Well, I did that, what's a setting now? :)
 
#5 ·
I know the screw you mean, I understand it was sealed in the factory, after they did an initial setting with a flow meter. I've checked my 1969 VW Dealership workshop manual, the screw is shown on the diagram, but even this official manual doesn't give any settings for that screw, doesn't even mention it in the carb stripdown & rebuilding instructions. I think you are going to have to experiment, to find a setting.
 
#9 ·
Konrad said:
In general idle is regulated by screw on throttle arm,
Click to expand...
No, the screw on the end of the thottle lever is the throtttle stop screw, it should be adjusted to allow the throttle butterfly to close completely, but without jamming in the throat of the carb. It should not be used to set Idle speed.
Idle speed is set with the idle control screw on the left side of the carb, (the one with the spring around it).
The small internal & sealed volume screw is factory set and controls the maximum volume which can flow through the idle system.
Fine control of that basic flow setting is done via the Idle control screw.
 
#11 · (Edited)
I think we have a misunderstanding due to terminology. I have a 30 PICT 2 on my 1500 beetle engine, and it certainly has a control screw in the left side of the carb body, it has a spring around it, to prevent it from moving due to vibration. Haynes manual and the VW official manual both call it the "Volume control screw", but that screw adjusts the idle speed, by altering the volume of emulsified fuel/air mixture going through the Idling drillings into the carb throat. Those drillings do nothing, unless the butterfly is closed.
I'm not happy with the drawing in your link, because, IMO, it's poorly annotated, and it's not for a 30 PICT 2 either.
You'll notice that your screw at the top of the throttle arm has no spring, and is difficult to turn, that's because you are not meant to turn it for regular adjustment purposes, it would have had a plastic security cap on it when new, to discourage adjustment.
It is only meant to adjust the position of the closed throttle butterfly in the throat of the carb.
If you adjust that to raise the idle speed, you are bypassing the idle control system, by preventing the butterfly from closing completely.
 
#14 ·
As I mentioned previously, there are no instructions for setting that sealed metering screw, in the official VW Manuals, as it is not really meant to be removed.
I'd screw it in until it stops, then back it off a couple of turns, to get an initial setting/starting point. Then try to set-up the carb to idle using the Volume control screw, if it does not respond to changes in the Volume control screw, but idles too fast, turn the little metering screw in half a turn and try again, continue trying, only move the metering screw in small increments each time, until you are able to adjust idle speed up and down by only turning the Volume control screw.
If, from the 'starting point', the Idle speed is too low, turn the metering screw out half a turn, and try adjusting idle speed on the volume control screw. Keep doing those adjustments in small increments, and you should find the 'sweet spot'.
A final check with an exhaust gas analyser will confirm if you've got the right setting for the little metering screw, but the usual checks for sooty spark plugs, or soot at the ends of the tailpipes should tell you what's happening in there.
 
T
#15 ·
30 PICT2 adjustment

Gentlemen.

I am obviously very late to this discussion. I found this thread while looking for an adjustment procedure for my 68 T1 which has the 30 pict 2. Hopefully you are still interested or have new information. What I have discovered conflicts with some of your recommendations or experience. What I have learned is:

- I did not know about the factory sealed adjustment you pointed out. I have not touched mine so I have no experience with the effects of turning it.

- The throttle plate stop screw is indeed used to set idle speed on this carburetor. Follow this link to the VW training film which specifically addresses the 30 PICT 2. The instructions you give not to use this screw to set idle speed are applicable for the 30 PICT 3 not the 30 PICT 2. See this vw video.

- The most useful thing I have learned however is of the presence of a third adjustment screw located on the top of the float bowl which angles in toward the carburetor throat. This adjustment is not shown on a single sketch of this carburetor or noted anywhere in setup instructions. It does however have a significant impact on how much effect turning the volume control screw has on idle speed and smoothness. Turning it out virtually disables the volume control screw's effects. Turing it in adds more effect to the volume control screw. It should also be noted that you cannot adjust this screw with the air filter installed. It also requires a very short and small screwdriver to adjust.

I do not know why this screw is not addressed anywhere in literature or why nobody seems to have tried to adjust it. It is more obvious than the other hidden adjustment screw and is only present on the 30 PICT 2. In my recent experience every single frustration I have read concerning the adjustment of this carburetor can be overcome by carefully adjusting the screw on top of the float bowl. This adjuster on my carburetor regulates the effects of the volume control screw.

Any thoughts or rcommendations? I'd like to put together an unofficial procedure for adjusting this carb but would like to assemble as much wisdom as possible.

Thanks.

Tom
 
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