34 PICT-3 Carburetor
Following are links to sub-topics under the general heading of "Carburetor" -
34 PICT-3 Carburetor
Loosen the little clamp that runs around the top of the carburetor and holds the air cleaner in place, and lift off the air cleaner (you may have to disconnect another hose or two to remove it completely from the engine compartment). Look down inside the carburetor (down the "throat"); there you will see a butterfly valve that may either fully close off the carburetor throat (if the engine is cold) and stand up fully open (if the engine is hot), or it may be anywhere in between. This is the choke valve, the function of which is to regulate the air/fuel mixture during cold-engine startup. It produces a higher concentration of fuel ("richer") when the engine is cold, then gradually increasing the concentration of air (making the fuel mixture "leaner") as the engine warms up. Details regarding choke operation are given later in this discourse.
Inside the bottom of the carburetor is another butterfly valve (you can't see it, but trust me) which opens to supply air and fuel to the engine. It is operated by the complicated lever on the left side of the carburetor, the throttle lever, which attaches to the accelerator cable which comes from the front of the car where it is attached to the accelerator pedal. On the throttle lever there is a return spring that returns the throttle lever screw to rest on the stepped cam on the left side of the carburetor. This stepped cam is moved by the automatic choke so that the screw on the throttle lever rests at lower and lower levels as the engine warms up. This assures that the engine has a high idle speed when cold (or it would stall), but the idle reduces to normal as the engine warm up. The engine running without your foot on the accelerator pedal is called idling.
On the right side of the carburetor you will find the accelerator pump. This is connected by a linkage to the accelerator; when acceleration is required, the pump squirts a spray of fuel directly into the throat of the carburetor to momentarily increase the fuel-to-air concentration.
Since 1967 there is another device on the side of the carburetor with a single wire leading to it. This is the idle cut-off solenoid -- it's function is to cut off fuel to the carburetor when the key is turned off. On the earlier 30PICT/1 and 30PICT/2 series carburetors the idle cut-off solenoid is in the right side of the throat and screws into the back of the idle jet. On later 30PICT/3, 31PICT/3, H30/31, 34PICT/3 and 34PICT/4 carburetors it's in the left side, close to the throttle arm and accelerator cable.
Notice the hose that comes into the top of the carburetor on the left side. This is the fuel supply line. It directs fuel into the bowl of the carburetor through a float needle valve (inside the carburetor bowl -- you can't see it without taking the top of the carburetor off). A float inside of the carburetor bowl opens and closes the needle valve to maintain the level of fuel in the carburetor bowl, similar to the float mechanism in your toilet.
Note:
One of the things that happens sometimes in a carburetor that will make your engine quit in traffic, start hard and generally screw things up is the float needle valve sticking so that no fuel flows into the carburetor bowl. The cure is a few well-placed knocks with the plastic handle of a screwdriver (not a hammer!) on the top of the carburetor bowl. If the car makes a habit of this, its time to rebuild the carburetor and replace the float needle valve, which is included in most carburetor overhaul kits.On the bottom of the carburetor bowl on the left side is a large nut. This nut is removed to provide access to the main jet which sits in the bottom of the float bowl. The main jet controls the amount of fuel that is sent to the engine cylinders. There are other jets inside the carburetor which we will describe later on.
If you look closely on the left side of the carburetor you will find one or two adjusting screws. The older carburetors have just a volume control screw, and the later models have both a volume control screw (smaller) and a bypass screw (larger). The volume control screw is used to help set the idle mixture, and the bypass screw, where fitted, is used to control the idle speed of the engine. So we use these screws to "tune" the carburetor. We will be discussing this process in more detail a little later.
Follow the fuel supply line down from the top of the carburetor to just below the distributor (the round orange or black thing with five heavy wires protruding from the top of it). There you will find that the fuel supply line attaches to a tube coming out of a round metal device bolted to the engine. This is the fuel pump. There is another connection point on the fuel pump with a metal or rubber line attaching to it. This fuel line runs around to the left side of the engine and forward through the fire wall. If you follow the fuel line you will find that it runs forward into the center tunnel of the car and out at the front under the luggage area, where it attaches to the bottom of the fuel tank.
Now return to the engine compartment. The bottom of the carburetor is bolted to the top of the intake manifold, a metal tube which splits right and left and carries the air-fuel mixture from the carburetor down to the sides of the engine, where it attaches to the cylinder heads on either side. If the intake manifold splits in two on either side, you have what is called a dual-port engine; if it continues as a single pipe froom head to head, your engine is single port. Under the horizontal part of the intake manifold in the center is attached a smaller tube, the heat riser tube, which brings up exhaust gas to heat the air-fuel mixture before it goes to the heads.
Inside the heads are the intake and exhaust valves. When the intake valve opens, the fuel/air mixture is sucked into the cylinder, where it is ignited by the spark plug. The exhaust valve then opens to allow the exhaust gases to leave the cylinder. More about the engine operation will be given when we discuss the engine in more detail later on.
The VW beetle engine originally used three different-sized Solex carburetors to suit different engine sizes, and each size has several variations, so lets look at them.
Note:
The carburetor model is stamped on the bowl on the left side of the carburetor. It is important that you know the model of your carburetor, as adjusting details vary somewhat from model to model.Until 1972 the Type 2 (bus/Kombi) also used the engines noted below, and in fact they got the larger size engines before the Beetle did. So the same carburetor types were used on the same engine when used in a Type 2, although they were often jetted a little differently to cope with the increased weight of the Type 2 vehicle.
The VW shops here in Australia usually recommend the H30/31 for all engine sizes up to 1600cc (including the dual-port engine), both because the 34s are very expensive here - almost $400 - and because the H30/31 is easier to set up. The H30/31 also tolerates the 009 distributor better than the 34 sized carburetor - less likelihood of flat spots.
The H30/31 carburetor has a throat only a mm or so smaller than the 34 anyway, so you should not see any significant drop in power (compared to the larger 34) around town - it would probably run out of breath a little sooner at high speed and that's about it.
The H30/31 is often delivered with very lean jetting (an emissions thing). so that should be checked before you use it (I’ve seen the main jet as small as 112.5). Lean jetting makes them hard to keep in tune. For a 1600cc single-port engine with a vacuum distributor, try a 55 idle jet, 125 main jet and 125 or 130 air correction jet. Leave the 65 power jet (right side) as-is - that's about the right size.
Note: You cannot use the larger 34PICT/3 carburetor on a single-port engine - the flange on the 34PICT/3 is too large for the single-port manifold. I don't think you can use a 30/34 adaptor upside down to fit the larger carburetor on the smaller manifold.
In summary, there are two replacement carburetors available today -- the Brosol H30/31 and the Bocar 34PICT/3:
Of concern to most people right up front is adjustment of the carburetor and the automatic choke, so we will address those topics first and then add a word or two about carburetor jets (including the cut-off jet), carburetor disassembly and cleaning, accelerator pump adjustment, air inleakage, flooding, vapor lock, and air cleaner.
Before you begin to adjust the carburetor, the valves, points, and timing should be set. This is important, and they should be set in the order shown, as we start with the engine cold, and finish with it warm. It's important to set the valves, points, timing and to check the choke before setting the carburettor, as they all work together for a smooth running engine. Details regarding these settings are given later in this treatise (Table of Contents).
The following descriptions apply to all types of carburetors -
Note:
You can test the operation of this solenoid very easily. Turn on the ignition (don't start the car), and pull off the wire on the solenoid. Touch the wire on the connector, and you should hear a clicking sound as the valve inside moves. If you do not hear a clicking sound, check for 12 volts on the wire (small trouble light, voltmeter etc), and replace the solenoid if necessary. If it's not working, you won't get a proper idle, and you'll get rough running at traffic speeds too.The 28PCI, 28 PICT, 28PICT/1, 30PICT/1, and 30PICT/2 all have one adjusting screw in the left side of the carburetor (the Volume screw) and an idle speed screw on the throttle arm. They can all be tuned using the "single adjusting screw" procedure on our web site, which is reproduced below -
The 28 and 30 Series Carburetors
Note: See the Tune-Up section regarding attachment and use of a dwell-tachometer.
That's it - you're done. The engine should be purring like a kitten now.
As for the single adjusting screw carburetors, it's important to set the valves, points, timing and to check the choke before setting the carburettor, as they all work together for a smooth running engine.
The 30PICT/3, 31PICT, H30/31 and 34PICT/3 all have two adjusting screws in the left side (the smaller Volume and larger Bypass screws) and a fast-idle screw on the throttle arm. They can be set using the "two adjusting screw" procedure on our web site, which is reproduced below -
H30/31, 31PICT and 34PICT Carburetors.
Note: You may find it easiest to simply note where the clamp goes on the cable end in this position (wide open), then let up on the pedal and make the connection with the system relaxed. Or, if working by myself, I find that I can come very close by adjusting the cable as follows: With the idle screw against the very bottom of the stepped cam, pull the cable back finger-tight and snug down the screw to secure the cable. It takes three hands -- I use my channel lock pliers and hold the end of the cable to the throttle lever while I tighten the screw with the other hand.
Note: This adjuster works with the choke to give a smooth idle on a cold engine.
Note: Make sure that the throttle lever returns completely with the butterfly valve fully upright. If the lever or the valve are sticking, the engine will run too fast and it will be impossible to adjust the carburetor. Just tightening (i.e., shortening) the return spring won't do it! If the throttle lever doesn't return completely, it could be due to misalignment, wear in the bore, too much friction at some point, insufficient return spring tension or interference (i.e., binding) with a related component. Part of our problem was interference between the accelerator pump linkage and the alternator.
Note:
You can check for a sticking throttle butterfly with the carburetor in the car. Disconnect the throttle cable, remove the top of the carby (choke section) so you can see the throttle butterfly down the hole, and operate the throttle arm by hand. You might be able to see if the butterfly is sticking or not. It won't be much movement of course it doesn't take much opening of the butterfly to get 1200rpm on an unloaded engine.Note: Screwing the Fast Idle Adjuster screw in more will increase the idle speed, but doing so messes up the Volume Control and Bypass Screw adjustments -- destroys the idle geometry, and the car won't run right.
Rob provided some wisdom here that is worth quoting verbatim:
"The correct idle speed is IMPORTANT with the 34PICT/3 carburettor, which is more complicated (and more sensitive) than the earlier types. It has three separate fuel circuits in it (only two in older carbs), and the 850-900 rpm idle is designed so the airflow through the carby is balanced for the idle circuit fuel flow. That's why it has both Volume and Bypass screws in the side (the earlier ones had only Volume screws). This way the idle speed can be set correctly using the Bypass screw without touching the screw on the throttle arm, which has to be set exactly right (just barely touching the very bottom of the stepped cam and 1/4 turn inwards no more)....that special sensitivity the 34 PICT/3 has."
So playing too much with idle speeds ruins the idle airflow and spoils the timing adjustments too.
Note: See the Tune-Up section of attachment and use of a dwell-tachometer.
Note: If you find it difficult or impossible to make these settings, it is possible that you could have stripped threads on any of these adjusters, a damaged hole for the tapered screw, or a damaged needle valve or O-ring.
That's it - you're done.
Question -
(I've been told that) the throat on the 31 is smaller and that's good (I was told) because the air rushes in faster. Any comment?
Response -
Well, yes, that's sort of right. The air speed through the carby is governed by the throat size, the engine capacity, and the engine revs. You need a partial vacuum in a carburetor to draw in the fuel from the float bowl. Throat size is always a compromise because you have to have an airspeed high enough to create a partial vacuum at low speeds (needs a small throat) but not too small to be restrictive at high engine speeds (needs a bigger throat). The engine would run on a carby designed to run a chain saw, but only at idle revs! And it might run at full throttle on a big V8 carby, but wouldn't idle at all.
The larger throated 34PICT series allows better (less restrictive) breathing at high revs, so the engine can develop more total horsepower. But it also has to operate at idle and cruising speeds. So the 34 copes with this by using 3 fuel circuits - idle, low speed and main. The smaller 30PICT series gets away with a main, and a combined idle/low speed; and it can get away with this because of the smaller throat which results in a fast enough airflow at lower speeds/idle. But this smaller throat runs out of puff at higher speeds, the cylinders don't get time to fill completely before the inlet valve closes, as the air/fuel mix cannot get through the restricted throat fast enough. So my 1600 with smaller 30PICT/2 carby makess about 55-56hp, where your 1600 with larger 34PICT/3 should make about 60hp (I think it was 60 for the 71 engine).
That's why (those who race their VWs) are always talking about dual 40mm Kadrons, progressive Webers etc. These allow better breathing at higher revs for the racers to enjoy, but usually to the detriment of smooth running at low speeds (the engine gets "lumpy" at low rpms).
A progressive Weber carburetor is a very good option but it takes a LOT of setting up to get it right. These have two throats, a smaller one for idling and gentle cruising about town, and a larger throat which only opens when you step on the gas. The Japanese cars used to use them a lot. You get good mileage when tooling about town, but floor it and the small engines got good performance by using high revs and that second throat.
The 31PICT will certainly run OK on (the 1600 dp) engine the first 1600 VW was the US 1970 model, which is virtually identical to my altered 1500. It had 1600 cylinders, with single port head and 30PICT/3 carby. Mine's exactly the same except that it has the original 30PICT/2 carby.
The 31PICT is a direct replacement for the 30 series, with (I'm guessing) some slight enhancements, and since the number is larger (31 v 30), the throat size is a little larger too, but not as big as the 34. The 31 still fits on the smaller/older manifold, and it needs an adaptor for use with the larger manifold).
Question -
Regarding a sticking throttle lever: Since the throttle lever won't return to the cam, it's impossible to set the idle screw on the throttle lever, thus making it impossible to set the idle with the bypass screw on the carburetor. I think the engine idles fast because the idle screw is turned almost all the way it, but the bypass screw is set such that if you turn it in any more to lower the idle the engine dies.
Response -
I tend to agree with you. As a start, try removing the cable from the throttle arm, and working the throttle arm by hand (holding the stepped cam clear). You might just feel something if you are lucky. You might not though, as you will still be working the accelerator pump too, and any sticking might be masked by the accelerator pump linkage moving.
Have a look at Bentley "Fuel System" fig 5 1 (section 2 of the book).
It shows a cutaway of the carby in good detail. The right side of the butterfly sits against the idle ports (one right opposite the edge of the butterfly, and three narrow transition ports higher up). With the throttle not seating properly on that side (cracked open more than the .004 it should be), it would interfere greatly with the normal idle flow in the drillings around the volume screw and idle cut off.
Incidentally, this diagram. shows the three circuit arrangement quite well. It's at idle in the diagram. and the only fuel shown is emerging through the lowest port. Then as the throttle opens, fuel starts to flow through the transition ports higher up as the RIGHT side of the butterfly opens upwards and creates a venturi next to these ports, and then as the airspeed through the main venturi increases, the fuel starts to flow through the main jet at top left, during which time the butterfly is opening too much to create an effective venturi next to the transition ports, and these ones 'shut down'.
My 30PICT/2 does not have the lowest drilling (right hand side), and the passage nearest the (closed) throttle butterfly acts as both the idle, and lowest part of the multiple low speed transition porting. There is no bypass screw on mine.
Question continued -
So I think the first thing I've got to do is figure out why the throttle lever is sticking and fix it.
Response continued -
One possible thing to try, is to loosen then retighten the throttle butterfly to the shaft. Probably not this causing the problem it should self align as the screws are tightened, but even a few thou out might cause it to stick, and this would also tell you if the screws are loose, which they should NOT be of course (probably two screws, and I think you get at them from underneath). Also look and the sides of the throat where the butterfly moves. You might be able to see bright 'rub' marks if the butterfly itself is binding on the sides, or on the outer edges (near where it closes).
Note - (Dave thinking out loud) -
My mind keeps coming back to the sticking throttle lever. (As I was walking in from the parking lot after lunch my boss was outside beating the weed. "Cute car, Dave, but it sure idles fast!" Tell me about it! I invited him over to the garage after work to fix it, if he thinks he's so smart!)
I really think this sticking throttle lever is the whole problem. It's sticking a good 3/16" out from the low point of the cam, and that's with the throttle idle screw turned almost all the way in. I can push it in, but I won't always be there with my finger to push it in when Mike lets off the accelerator! With the thottle open this much, the throttle valve is also open a bit--certainly much more than the .004 inch it's supposed to be. Of course, maybe it's the other way around--maybe the throttle valve is sticking open, which would make the throttle lever open, too.
Okay, thinking-out-loud time. As you said in one of your notes yesterday, if the throttle valve is not seating properly (i.e., .004 inch open) it will interfere greatly with the normal IDLE flow--i.e., fuel will be flowing through the transition ports higher up--which I assume would make the engine run faster.
The bottom line is--whatever is holding that throttle valve open, be it the valve itself rubbing against the carburetor throat, the shaft through the carburetor sticking, the accelerator pump linkage sticking--whatever: the result is the same--uncontrollably high idle.
So--before I can even begin to tune that engine properly I've got to find and fix whatever's holding the throttle valve open.
Note -
The normal VW carbies have just one throat (venturi). This is always open (it's called a "constant venturi" carburettor), so there is a huge variation in the amount of vacuum at the venturi, depending on how open the butterfly is, and of course the engine speed. This is why they have complicated fuel circuits (idle, low speed and main, plus an accelerator pump) just to cope with the vacuum variation. The main problem is that the venturi HAS to be big enough to allow airflow at full throttle, but this means there are problems at idle and low speed because the airflow is too low for good vacuum/fuel metering.
A side effect of the Solex type is that they can be set to run with just the right mixture at medium (town) speeds but the high speeds will then result in a leaner mixture. Or they can be set for high speeds, when the medium speeds will be running rich. Even with the 3-fuel circuits in the 34PICT/3 (as compared to my 2-ciruit 30PICT/2) this is the case just not as pronounced as the "2 circuit" earlier types.
Note -
I found that my '68 Bug does indeed have an air leak in the throttle shaft, so until I can do something about it I've tuned it like it had a 009 - timing advanced a couple of degrees, volume screw in a fraction (richer) and the accelerator pump set to max. This reduces the stumbles on acceleration (adds more fuel to compensates for the air leak), at the expense of a rough idle, but that will do until I can get a 30/34 manifold adaptor so I can use the 30PICT/2 off Bertie as a stand-in.
After talking to several places here, the preferred replacement is the H30/31, rather than the 34PICT/3 - they say they have less trouble with the 30/31, and although it's just a little small for the 1600, it only loses a fraction at the top end, which doesn't bother most folks for general running about.
I don't know what I'll do long term yet (one hurdle at a time), as they say that even a rebuilt 34 often gives trouble - they are just a very sensitive carby (as we well know).
Note -
I've removed the carby top maybe 10 times and still use the same gasket - no problems. It has a brass locating "pin" (actually part of a signal system for the choke I think" which makes it easy to line up again. I never use sealants on those gaskets, just rely on the screws holding it down.
Note -
The two NEW commonly available carbs for aircooled VWs these days are the Brosol or Bocar 34PICT/3, and the H30/31. The 30/31 has the same 24mm throat as the 31PICT and 30PICT, and the 34PICT/3 has the same 26mm throat as the older 34PICT/3s and 34PICT/4s.
If you can't find them locally, John Connolly at Aircooled.Net has them at a good price, and he will even jet them for you if you tell him what your engine set-up is.
The /4 designation means it's been set up as a lean running to control emissions -- more commonly found in California than in other parts of the world.
The /3 designation means the carb has three fuel circuits inside, and two adjusting screws on the left side.
The /2 of older carbs has only one adjusting screw in the left side, and has only two internal fuel circuits. For example, the 30PICT/2 (1968-69) has only one adjusting screw, where the 30PICT/3 is the same size but has two adjusting screws (used in the US only - in 1970).
The modern H30/31 can be used on 1200, 1300, 1500 and 1600 engines. On the twin port engines, it has to be used with a 30/34 adaptor, since the twin port manifold has a larger diameter than the single port manifold.
It must be jetted differently for the different sized engines, so that fuel flow will match the airflow characteristics, and they usually arrive jetted too lean.
Note -
The 34 carb won't sit on a single port manifold - the carby flange is too big. The 30/34 adaptor won't work either, it can't be "turned upside down" and only works to fit the smaller 30 series carbs on to the larger 34 sized twin port manifold.
Question -
I think the engine calls for a 30PICT/1 carb -- could this be why I'm having trouble?
Response -
The 30PICT/1 was originally fitted to the 67 1500s. 68 and 69 1500s got the 30PICT/2 and the 1970 1600sp got the 30PICT/3. They all have the same sized venturi (24mm) but have increasingly complicated fuel circuits for better mixture control. Any of the 30 series (30PICT/1, 30PICT/2, 30PICT/3 and modern replacement H30/31) will work fine with the 1500 and 1600 engines.
BUT - some of them (especially the 1970 30PICT/3 and the modern H30/31) were/are jetted super lean for emissions reasons. This was/is manageable when the engine was new and tight, but they become a problem when the engine and carby ages, gets the occasional leak, and so on.
Question -
I have a simple question on a Solex 30 PICT 2 carburetor. What does the bypass screw do? I have screwed it all the way in while it is running and it makes a small difference in the idle but not much. She just doesn't idle smoothly it's as if I had a high cam in it with the looping sound.
Response -
The 30PICT/2 is one of the most reliable Solex carbs. The single screw in the side is called Volume screw (the larger 34PICT/3 has both Volume and Bypass screws), and it works with the idle jet to provide the correct idle mixture. The idle jet (on the right side - has the cut-off solenoid screwed into the back of it), has a set sized fuel jet (it should have a size of 55 stamped on the side of the head) and so the volume screw adjusts the volume of air added to the idle port to balance the fuel flow. Screwing the Volume screw in reduces the idle air, so richens the mixture. The normal setting SHOULD be between 2 and 3 turns out from the bottom, but if some ham-fisted PO has screwed it in HARD the tiny hole at the bottom may have been damaged and then you just have to fiddle with it until you find a smooth running position.
The screw on the throttle arm controls idle speed with these carbs.
So you set the idle speed to 850rpm or so, then use the volume screw to get the fastest idle, then reset the idle speed using the throttle arm screw.
Note -
The design of the H30/31 is almost identical to the 34PICT/3 - it's just a smaller size (the 30/31 main venturi is 24mm, the 34 has a 26mm venturi). So if you follow the tune-up guide for the "two adjusting screw" carburettors on our site, you should be able to set the 30/31 up fine.
One thing though - the 30/31 is usually delivered with very lean jetting, and if you are using it on a 1300 or 1500 it may be OK, but if you have a 1600 in your 67, then it will almost certainly run lean, and be difficult to tune.
Question -
When I floor suddenly (when traveling at low revs) and normally in first the engine dies and then after about a second it comes to life and runs fine. Could this be fixed by adjusting idling?
Response -
Keep the idle speed up around the 800-900 mark, and set the Volume screw just on the rich side. Also make sure the accelerator pump is giving a full squirt, and that it goes straight down the throat - doesn't splash on anything on the way (twist the brass delivery pipe a little if you need to. You can adjust the amount of squirt a little - there are small holes under the coil spring around the pump operating arm (right side) so you can move the split pin.
Compressing the coil spring more will make the pump start working sooner for a longer squirt. Doing all that will reduce the hesitation somewhat. Oh - and make sure the timing is not retarded from normal at all, you could even try advancing it a degree or two (say 8-9 degrees at idle), so long as it doesn't start detonating under heavy acceleration. (more advance reduces flat spots a little).
Question continued -
I think I have figured out why when traveling in third or fourth at low rpms when I suddenly floor it jips and shakes a bit, I figure I'm flooding the engine and it can't pick up at those speeds!
Response -
I think that's more likely to be too low a speed for the gear (just over 30MPH in 4th is the minimum.) And the fractional LEAN hesitation would be part of the cause too. Have you checked and gapped the plugs lately - could also be one misfiring a few times before the rpm increase (poor mixture etc).
Question -
I replaced the volume screw when I rebuilt the carb a few weeks ago… As far as the hole being rearmed a bit, I looked inside with a flashlight but it's hard to tell ...
Response -
The carburetor metal is fairly soft and it wouldn't take much pressure on the screw to force the bottom of the hole larger, but you couldn’t see it with a flashlight down that tiny hole anyway. If that has happened, you just have to do the best you can or replace the carb.
Question continued -
The throttle shaft was humid from leaking fuel (not dripping but a little wet), so I guess it does have a vacuum leak. I know of a shaft rebuilt kit but I was told that it might not solve the problem …
I still can't explain why I have good idle and acceleration (could be smoother but...) when the volume screw does not work the way it should.
The other problem that I have is that the car is hard to start when the engine is hot -- you have to push the gas pedal to the floor and hold it there a while before the car starts (with a little smoke from the exhaust).
Response -
That almost sounds like it's slightly overchoked and getting too rich when hot (which would also explain why any vacuum leak wasn't causing too much problem (getting fuel through the choke system?). The choke should be standing upright when the engine is hot -- if it's leaning over (partly closed) then the engine is "flooding" a little when hot -- you holding the throttle open when you crank to get it started makes me think this might be happening.
The choke position is adjusted by loosening (not removing) the three screws on the retaining ring and rotating the choke canister under the ring. The are alignment marks on the ring and canister body so you can see how much it's moved.
Question continued -
So I guess I will have to install a new carb and live with the inscription ''BOCAR'' on the side... And the fact that the original throttle positioner with vacuum hoses and "altitude corrector" can't be connected to this new carb... which means less original...
Response -
The throttle positioner (never used here in Australia) just slows the rate of throttle closure when you lift your foot -- reduces emissions a little, and if your state doesn't require it to be fitted -- can be removed with no effect on the engine's performance.
The altitude corrector is unusual -- it was fitted to the Type 3 engines (notchback/fastback etc) but I haven't seen one on the Type 1 (Bug/KG).
Disclaimer stuff: Rob and Dave have prepared this information from their own experiences. We have not assumed any specialised mechanical knowledge, but we DO assume that anyone using this information has at least some basic mechanical ability.
We hope you find this information useful, but we don't take any responsibility for anything which happens to you, other people, your VW or any other property or goods resulting from your use of this material.
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Last revised 8 July 2004.
