Some tests to help you determine proper jetting. Others might find that the 30 sized carburetor on a 1600cc engine works better with a larger X127.5 main jet. > Servicing Keihin carburettor>07.78 . The speed of the engine (RPM) when it's doing this tells you which jet you need to change. As we learn more, we will include it here. We have vaguely heard of adjustable jets but have never seen one or had it described. Others are upset by a backfiring, or smoke belching monster. There is an pilot (idle) jet on all carburetors too - these are normally left at 55 for most carburetors (28, 30, H30/31 and 34 series), on any engine size (since it's only feeding the engine at small throttle settings anyway). As these plates restrict air flow, there is less vacuum to . Since Aircooled.Net has no control over product installation, we will not be held liable for any consequential costs or damages associated with products purchased. 60 day return. If the color is rich grey, you're about right. for IDFs, make the idle jet 1.25 the size of the throttle body. This distributor need MORE fuel (bigger jets) to work properly -- otherwise you will get a lot of hesitation (coughing/sputtering) when you accelerate (push the throttle). While it is necessary to enrichen the fuel mixture when running an 009 distributor, you don't want the any richer than necessary since it will use more fuel. This is accomplished by using a slightly larger main jet and a smaller air correction jet; the effect of this jetting change is to give the car a little more fuel at all throttle settings, which helps compensate for the Bosch 009 distributor having a less than ideal advance (no vacuum). This jet helps mix the fuel when the throttle butterfly is part way open, and so if you make it too big, it will let in too much air, and the engine will hesitate because of that. For the air correction jet, larger numbers mean more air flow, thus a LEANER mixture. Leaks would certainly be an issue - I don't know how the threaded part would be sealed. So, I let it warm up, and set the timing to 32 degrees full advance. The biggest problem I have with it was the fuel consumption. Product Description. I would stick with the 34 pict 3 carb with the dual port. Regarding fuel consumption as a function of jet size -- The 1600cc Beetle should get about 10-12km/l (24-28mpg). Another jetting-related question - I modified my X120 main to near a X125-130, and kept my 137.5Z air correction jets. And of course make sure that it's properly connected electrically to the connection on the coil where power is provided (the + connection) -- the lead can break off. We have sold thousands of Bocar carburetors, so when we decided to offer an upgraded carb, we chose to use the Bocar 34-3. The idle jet sits in a protrusion running down to the bottom of the carburettor, and the power jet sits in a protrusion running up to the top of the carburettor, so it's easy to tell which is which. It worked quite well, although the idle wasn't very accurate. We can only give a guide here, as engine age, type of fuel, carburetor wear, etc. The angled one (points slightly towards the rear of the car) is the idle jet. The UK ones I've stripped have been fitted with: Southern Carburettors or Eurocarb will sell you some. Discussion in 'Mech Tech' started by low_light_craig, Jun 9, 2017. On a 1600cc the main jet should be a size 127.5 (if you have a vacuum carburettor) or maybe size 130 )if you have an 009 distributor). Air correction jets are harder to find. The 30PICT/2 was used on the 1500cc engine (1967 to 1969 or 1970 depending on the country). I've used this particular carburetor with a 1600cc dual port engine and it works fine with the same main jet, but seems to like a fractionally larger X130 air correction jet (it runs a little rich with the X125 air correction jet). The power jet sticks straight out to the side, and sits in a protrusion nearer the top of the carburetor - if you remove that jet you can see a drilling straight through the carburetor body to the air correction jet/emulsion tube where the the main fuel supply is delivered into the throat of the carburetor. Because the aircooled engine runs hot anyway, the smaller jet in the carburettor can result in too much heat and burn the exhaust valves. (See the discussion of the air correction jet above.). You also set the accelerator pump for maximum stroke when using the 009. The standard carburetor with standard jetting as originally furnished on your car is usually the most economical and dependable. If not, I find that "canned air" (like Ultra Jet or similar) works pretty well. Do not allow cleaning solvent to come in contact with skin. The H30/31 is the largest carburetor you can use with the normal single-port manifold. But different gears and different rpm doesn't. does anyone have a link to a graphic that explains where it is on the carb? The extra advance helps reduce the 009 flat spot just a little. For the 1600cc engine, you need more fuel flow, so a larger X127.5 main jet and 100Z or 120Z air correction jet are needed. When you work out the area of the hole in each jet, the steps are roughly 2% increase in fuel flow for each size up (X125 to X127.5 for example). We are still processing and shipping orders from our warehouse as normal even while our site is offline. I also have a stock carb rack but it appears to have water damage and one or more carb is seized. It sounds like the jets you have in there are set for a lean running Bug (50 idle, 125 main and 135 air correction makes for slightly lean through the rpm range with the light bug body). 2. Make sure the old one you took out stays in good shape so it can be reused. Carburetor-to-intake manifold gasket. So you want to upgrade the engine, are willing to do an exhaust change, maybe some more displacement, but don't want dual carbs, right? You should see some air come out of the progression holes in the carburetor throat just near the throttle butterfly when it's in the closed position. There also is an EMPI replacement 30 Pict-1 with the Pilot Jet . SOLEX 34 PICT 3 Carburetor Adjustment Procedures. I have recently rebuilt a 34-PICT 3 for my bus with a S.B. Note: Dave found that none of the gaskets in his kit fit his carburetor. Note: Compare the new float valve with the old one. A All three of these jets can be changed. Dave replaced the main, idle and air correction jets so he knew what he had. In either case, spending the time to properly jet your carburetor is a very worthwhile task. FreeShipping. Most carburetors come out of the box with a 55-60 idle jet. DP case, 1641 P & C, w/ Scat C25 Cam, & stock heads. Rob's note: When removing the main jet, I use a small glass jar (pickle or baby-food jar) to catch the fuel from the brass plug - I hardly spilled a drop (I just allowed the plug to fall in to the jar), and used the fuel to refill the float bowl later. The idle cut-off valve is not strictly a "jet," but this is a good place to discuss it. and 34-3 carb. Sounds like a good starting point! Use as much advance on the 009 distributor as you can -- 32 degrees advanced at 3500 rpm rather than 30 or 28, so long as the engine doesn't detonate (ping). The only method of getting it exact is to run the car on a dynomometer with an exhaust gas analyser in the exhaust pipe. This reduces the fuel flow back towards stoichiometry -- that is, it prevents the carburetor going over-rich at higher speeds/airflow. mains: 120, 130, 135, 145. air jets: 160, 170, 180, 185. ANY SINGLE THING other than stock, Berg Semi-Hemi heads, 009 distributor, extractor exhaust, etc. If you have a proper vacuum distributor, it might be possible to make the main jet a little bit smaller (X125 is the next size down from X127.5), but this will not make very much difference in the fuel consumption. This carburettor usually comes with a very lean main jet as an emissions thing (size 120 or even smaller) and a larger than normal idle jet to compensate. Assuming a vacuum distributor, the 34PICT/3 carburetor is usually jetted with a X127.5 main jet, and 100Z -120Z air correction jet. This is not correct. Details. Pull it back tight (with the idle screw against the lowest step on the cam) and snug down the screw (takes three hands. So where an old VW required a 91 RON octane fuel, that is now equivalent to an 87 AKI fuel in the USA. The power jet only works at higher throttle positions and higher rpms. If it's not, the float bowl will overfill through the bowl vent down the throat of the carburetor, causing the fuel/air mixture to be WAY too rich - and of course the exhaust will spew out a lot of black smoke and the engine will not run. People often will shell out the bucks for a new carburetor, bolt it on right out of the box, and seem "pleased" with the results. The old one for a pattern and a sharp hobby knife or box cutter works well. The back one (pilot?) Jet-A-Vator. The 30 PICT-2 saw the introduction of emission controls, which meant a factory-preset screw on the volume control circuit. Jetting With the Centrifugal-Advance (009) Distributor, Tuning the 009 Distributor/ PRICES are subject to change without obligation. Note: Do not soak the choke heating element, pump diaphragm, float, vacuum diaphragm, or any other rubber or plastic parts in carburetor solvent. SUPER-STOCK-34-3. Main jet sizes run through a range from X110 to X150 (1.1 - 1.5mm diameter). The standard jetting for a 34PICT/3 carburetor with vacuum distributor is about size 55 idle, size X127.5 main, and size 100Z-120Z air correction jets. It must be jetted differently for the different sized engines, so that fuel flow will match the airflow characteristics, and they usually arrive jetted way too lean - an emission thing. The power jet is usually a size 65. Now unscrew it exactly 2-1/2 turns. the size 65 power jet should work fine for those conditions. The effect is not linear though, so as the airspeed increases, the main jet will start to deliver a richer mixture (too much fuel), so the air correction jet is needed to add air and stop the mixture going over-rich, then the air correction jet starts working too well at higher airflows (engine revs) so the Power Jet (Aux jet) is need to add more fuel again. I have 4-5 I've collected over the years, and the smaller ones can be re-drilled to the larger sizes. Unscrew this bolt and look at it -- if there is a jet screwed into the bolt (older models), you can deal with it in hand, so to speak. and jet > size. Special Instructions The air correction jet doesn't affect idling very much since it helps control the mixture at higher rpms, but worth a look to see if you have a fuel blockage problem in the carburetor. It is still UNCERTAIN, but we may re-open a substantially downsized version of our store again in the Spring of 2023. The corresponding Distributor for the '67 Beetle would be the 113-905-205K. The jets in Dave's 34 PICT/3 carburetor are - Main jet - X130; Idle jet - 55; Air correction jet - 80Z ~~~ Jetting With the Centrifugal-Advance 009 Distributor, The 009 centrifugal-advance distributor can not sense throttle position engine load, only engine revolutions, so it's not ideal in all circumstances, Changing the jetting in . Dave bought a Pierburg model 34PICT/3 carburetor from Aircooled.Net, and none of the jets had the sizes stamped on them. Email care allows us to provide important service detail that can be later referenced by both the customer and our care staff. With the idle cut-off valve working correctly, hot spots in the cylinders don't occur as readily, since there is no fuel available to keep the engine running once you turn off the ignition. Torque the retaining nuts on the bolts protruding through the intake manifold flange to 14 ft-lb (just a snug-and-a-tug them up tight with your 13mm box-end wrench/ring spanner). Sorry! On the H303/1 it is often oversized too - a 65, used to stop the engine stalling at low rpm as the main jet supplied with these is often VERY lean 117.5 or 120. were visibly larger in the new jets than the old ones. This will richen the mixture and help eliminate any 009 flat spots. Carburetor Disassembly 34 pict 3 carburetor overhaul Jan 27 2023 web the proper float valve washer 4 must be used for the specific type of carburetor the 34 pict 3 carburetor uses the 0 5 mm 020 gasket a micrometer . First - Muir above was writing in the 1970s, before the USA changed their octane rating system, and also before Ethanol became common in fuels. If you are using a 009 distributor with a 30PICT carburetor on a 1600 cc DP manifold, the main jet should be X130 or X132.5 and the air correction reduced to about 100Z. The 1600cc DP can flow more air than the 1600cc SP and smaller engines. Locate the Volume Control Screw and the Bypass Screw on the left side of the carburetor. almost all the way to the top.-the idle 'cut off' solenoid clicks repeatedly when tested. Rob replaced the air correction jet with a 140Z, and at low-middle speeds there is no discernible effect. The 34PICT normally has a X127.5 main and a 140Z or 170 air correction jet. Items that are not expected to be restocked within 2 weeks WILL BE AUTOMATICALLY CANCELLED. With a leaner 140Z air correction jet in the carburetor) I got 11.6 km/l (27.5mpg US). That means that the jetting requirement for any VW using ethanol-added gasoline/petrol is different to those using straight hydrocarbon gasoline/petrol. All suggestions here are just that - suggestions. The valve on the Pierburg carburetor has a spring-loaded ball bearing on the end; it is likely that the valve in your kit does not. Another well respected and active VW carburettor rebuilder is TIM. So VW chose this configuration. For example, the X130 main jet is a tad rich for the vacuum dizzy at sea level, so if the car is to be operated at a high altitude it will be running very rich, and you might get a smoother engine and less exhaust soot with an X127.5 or even an X125 main jet (the "right" size for 5000 feet altitude). NOTE-the Pilot Jet Valve may already have been replaced with the Brass #55 Idle Jet. Or should I open what I have or rob from a newer model? The standard jetting that the 30PICT/1 & 2 carburetors came with is size X122.5 or X125 main, size 55 idle, and size 125Z air correction jets. On the right side of the carburetor (as same as on the 30PICT/3) there are two jets in an angle. Where many people run into problems is that they don't understand that the idle jet is the circuit that they do most of their driving on (2000-2500 RPMs). The fiddly bit is pulling the jet back through the hole. Note: It is very important that you install the correct needle seat gasket. Well, if the fuel/air mixture is too rich, the extra fuel will wash the film of oil off of your cylinders and wear out your pistons, cylinders, and rings quickly. Replacing the main jet in is super easy -- just put it in the hole in the side of the carburetor, then put the screw driver in after it and slide it along the 'valley' that runs across the bottom of the float bowl. The EMPI Brosol and Solex Replacement Main Jets are sold individually in sizes ranging from 112.5 to 170. Normally, shops stock them in round sizes of "5"s, like 50, 55, 60, etc. Once again, try the conservative approach first, then get richer only if you have to. . On the premise that the 1600cc engine likes to run just a tad rich, many people will change out the main jet for a size X130. Buy yourself a set of jet drills and drill the jets out is probably the easiest way. So how do you know which to use? It provides fuel at low medium revs too, so if it's not working you'll get a rough idle and lean mix at lower revs. = Uses .0 Bypass: WEBER 34 ICT: Factory Sizes: Single Carb: Dual Carbs: AIR CORRECTION 1.60 N/A 1.60 EMULSION TUBE F-78 N/A MAIN . All Solex carburetors tend to run lean at high power settings (high rpm and open throttle). The sizes are stamped in tiny numbers on the heads of each jet. Rob provided further explanation: The idle circuit is behind the main jet - the fuel flows THROUGH the main jet to get to the idle circuit. Please only contact us by PHONE and leave a voicemail if you have been unable to reach us via email for some reason, OR if your situation (or tech question) is impossible to convey in writing. But optimum performance and MPG will be achieved when you use a wide band and tune the carb for 16:1 A/F on cruise, and 13:1 over 1/2 throttle. Both clearances are essential; If the accelerator pump linkage rubs on either end, the throttle lever will not be able to return all the way to the stepped cam, the result being an excessively high idle that cannot be controlled with the bypass screw. The larger size 65 idle jet helped the 30PICT/3 and H30/31 carburetors overcome the very lean main jet at idle and low speeds, and thus help to reduce the "bogging" problem. The auxiliary (power) fuel jet is a small brass jet screwed into the right side of the carburettor, sittin in a protrusion running up to the top. But optimum performance and MPG will be achieved when you use a wide band and tune the carb for 16:1 A/F on cruise, and 13:1 over 1/2 throttle. It should not be possible to blow air through the valve while the needle is pressed lightly onto its seat. 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