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Thu Jun 07, 2012 4:32 pm

I have a 1973 standard beetle with 1600 dual port, Solex 34 Pict 3 carb, w/ electric choke. When I start the engine cold, choke is fully open and gradually steps down on the choke cam as designed. Runs perfect when the choke shuts off for extended period at idle. Problem is, once I step on the gas, the choke will step up one notch on the cam and then the engine stalls. Does this mean the choke is set too rich??? If so, what would be the fix & how??? I'm new the the VW world. The engine is completely stock with fresh points & cap, plugs & wires, coil, vac hoses. fuel pump, oil change, electrical wires, clutch, valve adjustment, rebuilt carb, gaskets, etc. All tin, heater boxes, etc are intact. Only thing not working is the preheat flap in the stock air cleaner. This car will only be driven in PA summer weather. All engine work was done by and old VW mechanic when the motor was out of the car approx. one year ago, prior to me purchasing the car. I currently have the entire frame/suspension/brakes restored with engine reinstalled, but body off. Intake manifold does sweat/condensate when running in 70 degree temps, if this helps. Thanks in advance

Mon Jun 11, 2012 5:59 pm

The choke probably just needs a minor adjustment., This can be done by loosening the three screws on the bracket holding the choke and turning the element a bit.

Tue Jun 12, 2012 7:38 am

it means :
1: set wrong
2: bad choke. coil (the bi-metal coil dont last 40 years, not ever)

the top of the choke body has a scale, see that?
set it to the max lean side. (cw side is lean, )
then when the coil heats up. it opens 100 %

the coil heats via the heater (30 -45 ohms) the heat heats the bi-metal
and it uncoils and opens the choke. 100% if not 100% its wrong.

note how far chock closes cold
then note how for it opens hot.
100% hot
and mine closes this summer about to 1/4" in the bore. 90f

Tue Jun 12, 2012 8:35 am

myrenovator, you've posted this in another thread:
http://www.thesamba.com/vw/forum/viewtopic.php?t=21849

But I suppose it is best you had your own thread for this question. :)

I replied in the other thread:
myrenovator wrote: I have a 1973 standard beetle with 1600 dual port, Solex 34 Pict 3 carb, with electric choke. When I start the engine cold, choke is fully closed and gradually steps down on the choke cam as designed.

A cold choke coil should be trying to CLOSE the choke butterfly. Before starting the engine you should step on the accelerator pedal enough to release the throttle arm's hold on the step cam. The cold coil spring should slam the butterfly shut.
Once the ignition is ON the choke coil starts to heat up and the butterfly will start to OPEN as the coil loosens. As it opens the weight of the cam will rotate the butterfly OPEN and the throttle arm screw will rest on progressively lower steps.

myrenovator wrote: Runs perfect when choke shuts off for extended period at idle. Problem is, once I step on the gas, the choke will step up one notch on the cam and then the engine stalls. Does this mean the choke is set to rich??? What would be the fix???

It could be your choke coil is old. After years of heating/cooling they loose their range of motion. My old choke coil would not close enough when set to few fully open when warm. If set to fully closed when cold it would not open enough when warm. A new coil fixed that.

There is also a vacuum activated piston that forces the butterfly OPEN (I think?). I believe the function is to open the choke butterfly when increased flow is needed.

You should also check the choke butterfly moves freely. The choke opens with just the weight of the choke cam. Remove the three screws that hold the choke cover and remove the choke coil. The butterfly should fall OPEN with just the weight of the cam. If it gets stuck, you will need to clean, straighten or lube the linkage.

Tue Jun 12, 2012 9:05 am

yes that diaphram is for bad drivers
they try to flog the engine cold
so it opens the choke via vacuum drop.
this prevents instant flooding and or engine damage from raw fuel.

vacuum choke unloader.
there are many choke settings and tests.
1: does it close cold"
how far?
2: does it open fully hot ( no)
3: is it set correctly? do you have a book? page S3-p12 in the bentleys?
4: does the vacuum choke unloader work?
5: does the stepped cam work both hot and cold
6: is the stop pin missing or sheared in #5 ? causes super fast idle all the time.
look even if not doing that, because it can latch up and cause an accident.
"be on TV like the Toyota folks" no !

in warm weather the choke does not close 100%
i run mine on the top Cw notch
the Bentleys spends 2 full pages on how it works but not a word to set it.
i set min to lean side.
that way motor is happy and rings happy.
if at any time mine seems too lean , i richen it a tad.
if the spring acts old, that is not closing proper or not opening fully , i replace it.
some find and old spring don't close the choke proper.
so they over correct and set it richer, only to find out the choke never opens fully hot, this is a bad bi-metal spring. and a bad user.

i love manual chocks, but on VW it's a hard install., every car i run manuals.

Tue Jun 12, 2012 10:55 am

I have had success with this way of adjusting the choke:

1. Make sure that the carburetor has a typical temperature of the time of year. That means, in the summer, do your adjustment in a "typical" day. In the winter, do it on a typical day for your climate.

2. Open the three small screws on the lock ring around the choke lid

3. Turn the choke lid (the one stamped SOLEX) so that the choke throttle just closes.

The one in the picture needs adjustment. Well, actually, not. I had it in the fridge over the night. I wanted it adjusted to a climate just above freezing temperature. When this picture was taken, it had been in room temp for a good while. Here you see the difference - far too lean for a cold start on a cold morning.

The choke should be adjusted at least once each spring and once each late fall to get it right.

Wed Jun 13, 2012 6:59 pm

Thanks for all the advice. I'm going to order a new choke coil. The choke butterfly will not open fully, even after the engine warms up. I tried adjusting the choke but it doesn't help at all.

Thu Jun 14, 2012 10:32 am

Your choke coil is connected to a 12v power source, right?

If you remove the three screws and the entire choke coil, does the choke butterfly open all the way? This indicates that the choke coil is preventing the butterfly from opening and not something else interfering with movement.

Thu Jun 14, 2012 4:00 pm

i don't do that at all . sorry !
the electric choke is crude device, a water choke is far better. OMG H20 leaking,.... run.....

EG; i cant scoop up hot air from my heads and wrap that around my choke, sadly, only a water car can pull off that magic.... and really works....

i set mine to a tad lean, and add rich till i'm happy, cold running.
the less choke the better! for you lungs, your engine. and rings.

the better the burn the faster the motor warms up.
A 2nd GOOD.
Many goods , no?

the chokewill close more, all by its lonesome, due to that magic bi-metal spring inside.
let it. (don't try to out smart it, you are smarter, so it's a waste trying..)
like a dog on a leash , you kinda guide it....

less is more, try it, learn from it....

and rule 2 , don't be afraid to re-adjust it, in the fall or winter? fear not !

and even replace, it getting a fresh spring, so it acts SMARTER.

It is vastly far from a perfect device, and not even SO SO...

My lean is just enough to drive off gently and warm it even faster.
DIG? (I'm like muir (mr, no choke) only try to work what is there...)

not sure if the above is fact, but worked for me 1000 times
but consider this....
Quote: What can you do against the lunatic who is more intelligent than yourself, who gives your arguments a fair hearing and then simply persists in his lunacy? G.Orwell

I think anything, is possible, and that my ideas are accurate.
But at no time do i consider them perfect. after all i've never touched you POS, just my POS. Some faults add, others subtract and others, Chaos.......

Thu Jun 14, 2012 4:21 pm

Quote: it wont open fully
i adjusted it and it dont open , it must.

1: it's not indexed in side, some PO buggered it up.
2: the linkage is jammed up, this is easy test.

the bentley's covers indexing
'the end of the choke spring fits in linkage just so, not by guess.

there are lots of possible mess ups. all linkage
even the vacuum unloader can be jammed or spring put on wrong
or the fast idle cam is jamming or bent, or , gee, it's mechanical and needs
hands on fixes...

take the choke cover off
now its not there. no spring. or cover
next, open the throttle.
this act releases the choke.
do the choke fly plate flop from side to side like a bird wings? no? bad.
fix bad.

i do admit it it is easy to assemble a carb 1000 wrong ways.
for sure. takes patience.

still no photo of your carb, making truly expert help, well, near impossible....
i for one have not seen every derivative. carb for this type. BOCAR? is it .>?
other here have, some even pray at knight never to see another......

above carb is a real Solex made in Germany ,not brazil or mexico ,like OPs.
and OP carb, has dead choke, not maladjusted, but if you consider
misadjusted inside (indexed wrong) then true. but that is an assembly error.

show actual carb.
or video of it messing up.
seeing is believing....

i wish we had a BOCAR to original Solex comparision
what is different
my guess is , its just SVDA carb, frozen in time...
with one vacuum nipple , correct>?

1971 SOlex 34pict 3 (22 base flange models to 1974)
to
2004 Bocar 34Pict 3? (? variants?) Mexican.

how do these vary in design?