| Author |
Message |
airschooled
Air-Schooled
Joined: April 04, 2012
Posts: 12727
Location: on a bike ride somewhere
|
 Posted: Sat Oct 31, 2015 12:40 pm Post subject: Throttle positioner, Control valve with High altitude corrector! |
 |
|
“What is this thing? Do I need it?”
The throttle positioner. Yes.
Photo courtesy of wcfvw69.
Background:
In 1967 (model year 1968 for our Volkswagens) the Federal Air Quality Act was enacted. In addition to allowing California to set its own stricter emissions regulations, due to its larger pollution base, it amended the 1963 Clean Air Act and focused on regional issues and stationary power produced emissions.
From www.arb.ca.gov:
| Quote: |
| Federal Air Quality Act of 1967 was enacted. It established a framework for defining "air quality control regions" based on meteorological and topographical factors of air pollution. |
http://www.arb.ca.gov/html/brochure/history.htm - accessed 11/1/15
However, the 1967 act did not go far enough, as the public did not feel the pace of improvement was acceptable. Enter the Clean Air Act of 1970, (1971 model years for us,) which moved far more aggressively to limit emissions of mobile sources. (Remember, Volkswagens were still new then, so they were in fact mobile! …since no one was using them as chicken coops yet.) The Environmental Protection Agency was also founded this year, along with the holding of the first Earth Day, on April 22nd, 1970. What kick started this year’s movement, was the signing of the National Environmental Policy Act. This is considered by scholars to be the “environmental Magna Carta.”
Raw gasoline practically belches hydrocarbons, which can combine with other gases to create a majority of smog-based health hazards. I am not a chemist, so I will not attempt to explain the course of chemical evils, but just remember that more than 99% of pollutant gases are invisible.
What it does, and how it works:
The air required to run an internal combustion engine must flow through the carb in such a way that it draws in just enough fuel for a complete burn. However, we know that different engine conditions require different mixtures, so carburetor technology has changed over time to allow the proportional mixing of air and fuel when the engine requires it. When the engine does not require much air and fuel, like when you release the pedal and the engine returns to idle, carburetors are extremely ineffective and inaccurate at mixing air and fuel.
When a piston goes down and “sucks” in intake air and fuel in, it creates negative pressure in the intake known as “vacuum.” The level of vacuum is dependent on engine speed, (how fast the cylinders are pulling air in,) and throttle position, (how much air volume is allowed in due to suction.) Imagine that you are traveling at a high RPM on the freeway, and you let of the pedal immediately because you were hastily cut off by a Prius driver who looks at the fuel economy gauge instead of the speedometer. “But it says 65!” The pistons are sucking air mightily, and the throttle plate is trying to cut off airflow, so the vacuum, or suction level, in the intact tract is extremely high. This creates a sudden influx in fuel, because of the sudden increase in air suction. But your Volkswagen doesn’t need the fuel!
Enter the throttle positioner. By using a mechanical linkage to detect these spikes in intake vacuum, the throttle positioner actually holds your throttle arm and throttle plate open a tiny bit while the engine slows down. This reduces the fuel dumped needlessly through the engine, preventing raw gas from fizzling out your tailpipe.
The mechanical aspect of the linkage is simple. There is a vacuum diaphragm inside the positioner arm, and when your intake manifold vacuum is high enough, it pulls the arm. Just like a distributor vacuum advance can. The amount of vacuum produced by the engine depends on many factors, like age, wear, cam profile, and timing, so adjustments can be made. Inside the assembly underneath the brass screw is a bellows that can compensate for vacuum changes. Bentley calls this the “altitude adjuster,” as vacuum levels greatly change with “elevation.”
Differences in models:
1968-1969 model year bugs and buses came with the one piece style positioner, which includes the actuating arm/diaphragm and adjustment screw/bellows in one housing. The one-piece throttle positioner mounts directly underneath the carburetor, and requires an additional gasket to the intake manifold. There is only one vacuum port, and it receives full manifold vacuum from a nipple on the intake manifold.
An example of a correctly functioning one-piece throttle positioner can be seen here, courtesy of wcfvw69:
Link
1970-1971 model year bugs and buses came with the two-piece style throttle positioner, which functions almost identically, but is split into two pieces. The two-piece unit has two vacuum hoses as well; one hose goes to an intake manifold vacuum port, but now the other hose goes to a new vacuum nipple on the 30pict3 and 34pict3 carburetors.
The actuating arm is still mounted to the carburetor, except now it looks like this:
The adjusting part is now located on the left side of the engine bay, in both bugs and buses.
Photo courtesy of busdaddy.
Photo courtesy of celticbob.
What else it does/alternate names:
The throttle positioner can also be called the shift enhancer, smog device, ride smoother-outer, backfire eliminator, and my personal favorite, unnecessary. It is all but one of those things.
By slowing down the throttle plate return on a carburetor, the engine stays at a slightly higher RPM when you upshift. This creates a smoother transition into the next gear, creating greater comfort and pleasure for drivers and passengers alike, IF you care about such things. This also matches the transaxle input shaft speed more closely to that which is required for the next gear. This puts vastly less wear on your synchronizers in the transaxle, and you SHOULD care about that.
We’ve already discussed how it can avoid dumping the gas out the tailpipe for emissions reasons, but does your car gurgle and fart on long downhills with the throttle shut? The throttle positioner purifies the air/fuel mixture on throttle overrun, so these little queefs of the car will be reduced or eliminated as well. Unless you have an exhaust leak. Get that shit fixed.
Installation and adjustment:
As a general rule, your car can use the one-piece throttle positioner if you have a vacuum port below the carburetor mounting flange on the intake manifold. As the second general rule, you can use the two piece throttle positioner if your carburetor has the angled vacuum port on the right side, (shown here in red,) AND a similar vacuum port on the intake.
It is worth paying special attention to the mounting brackets, regardless of which type of throttle positioner you choose to install. The 34pic4 carburetor has a larger base flange, so it requires the 1971 one-year-only mounting bracket. All other carburetors interchange mounting brackets. In addition, both the one-piece and two-piece positioner use the same “ring mount” style, so you can mix and match parts to get a mount and a positioner that works with your setup.
With the one-piece positioner, the factory provided a vacuum port just below the carburetor flange for your hose to reach. Since parts get swapped and all three of us that care about throttle positioners can’t be evangelical enough, your vacuum port may be on the left side of the intake down pipe, or on the far left by the cylinder head part of the manifold.
With the two-piece positioner, the angled carburetor port is always near the diaphragm connection, and the factory vacuum port for the second connection is on the left side of single port manifolds, and cast into the #3&4 end piece of the dual port intake manifold. Regardless of where your hoses end up, notice how the two ports are of different sizes? Standard distributor vacuum hose works for the smaller size, and 5mm (fuel hose size) vacuum hose works for the larger connection.
Adjusting the throttle positioner is detailed quite thoroughly in Bentley. Whaaaat you thought I was going to spoon feed it to you? HA! I will say your carburetor needs the secondary throttle arm to attach the mechanism to; without it you're out of luck.
Final thoughts:
Your car will run without the throttle positioner. Most take it off and throw it away, but some sell them to me for a couple bucks. I have enough spare to last my lifetime, so now it is time for you, good reader, to peruse the classifieds and junk yards of the world and get your engine working like it is supposed to.
wcfvw69 has a thorough article on rebuilding the one-piece positioner. The two-piece positioner will be rebuilt the same. Usually, I see two-piece positioners need nothing but a cleaning and one-piece positioners needing a diaphragm of some kind. Nitrile sheet gasket would be ok, but viton would be best for recreating the diaphragms using the old ripped ones as templates.
http://www.thesamba.com/vw/forum/viewtopic.php?t=637886
Remember how I said the two types function almost identically? Since I am feeling tired of typing, I will offer a prize to anybody who can tell me WHY Volkswagen went to a two-piece system. Answer in complete sentences, and perhaps explain the major functional improvement please. 
Love and good air quality,
Robbie
_________________
Learn how your vintage VW works. And why it doesn't!
One-on-one tech help for your Volkswagen:
www.airschooled.com
Last edited by airschooled on Sat Oct 31, 2015 1:03 pm; edited 1 time in total |
|
| Back to top |
|
 |
Tcash
Samba Member
Joined: July 20, 2011
Posts: 12844
Location: San Jose, California, USA
|
| Posted: Sat Oct 31, 2015 12:51 pm Post subject: Altitude Corrector t2 |
|
|
Throttle positioner, Control valve with High altitude corrector!
Thanks to jerseylooker
| stevo_2006 wrote: |
here it is it is technical called Altitude Corrector
|
| Karl wrote: |
An 'altitude adjuster' adjusts your mixture for the altitude you are driving at. i.e. it compensates for the change in barometic pressure.
I have NO idea why VW is calling the decel valve compensator an 'altitude adjuster'!!! All it does is adjust the throttle plate postition when you let your foot off the throttle. To stop an over-rich condition.
It does not change mixture one bit. |
| busdaddy wrote: |
I've found if I fiddle with my altitude compensator/decel valve controller and get it just right it'll automatically raise the idle when it's really warm out, not sure if it's meant to do that but it sure comes in handy.
Running it at a fast idle before shutdown is standard operating procedure for piston powered helicopters, 2-3 minutes until the oil temperature and CHT are down to the recommended levels, reduces cracking and baked on oil deposits. |
Last edited by Tcash on Sat Jul 02, 2016 7:08 pm; edited 2 times in total |
|
| Back to top |
|
|
AircooledHome
Samba Member
Joined: October 13, 2015
Posts: 273
Location: California
|
| Posted: Sat Oct 31, 2015 1:36 pm Post subject: |
|
|
Yay thanks!  |
|
| Back to top |
|
|
aeromech
Samba Member
Joined: January 24, 2006
Posts: 16971
Location: San Diego, California
|
| Posted: Sat Oct 31, 2015 2:02 pm Post subject: |
|
|
Robbie, couldn't you have been a bit more thorough? I mean really, we need the whole story. 
_________________
Lead Mechanic: San Diego Air and Space Museum
Licensed Airframe and Powerplant Mechanic
Licensed Pilot (Single engine Land)
Boeing 727,737-200-300-400,757,767
Airbus A319,320,321
DC9/MD80
BAe146
Fokker F28/F100
VW type 1 1962,63,65,69,72
VW Type 2 1971 (3 ea.) 1978, 1969
VW Jetta
VW Passat
Capable of leaping tall buildings in a single bound |
|
| Back to top |
|
|
airschooled
Air-Schooled
Joined: April 04, 2012
Posts: 12727
Location: on a bike ride somewhere
|
| Posted: Sat Oct 31, 2015 2:23 pm Post subject: |
|
|
| aeromech wrote: |
| Robbie, couldn't you have been a bit more thorough? I mean really, we need the whole story. |
I withheld the ending! You gotta play for a prize! 
_________________
Learn how your vintage VW works. And why it doesn't!
One-on-one tech help for your Volkswagen:
www.airschooled.com |
|
| Back to top |
|
|
Alpha_Maverick
Samba Member
Joined: May 01, 2011
Posts: 626
|
| Posted: Wed Nov 11, 2015 5:14 pm Post subject: Re: Introduction to throttle positioner and altitude adjuste |
|
|
I assume you mean OTHER than making it easier to get the engine out of the car?
_________________
| Alstrup wrote: |
| hmm well, wiggly I like 5,5inchers in the rear at least. |
|
|
| Back to top |
|
|
mattlockwood
Samba Member
Joined: June 15, 2012
Posts: 360
Location: KCMO
|
| Posted: Thu Nov 12, 2015 1:22 pm Post subject: Re: Introduction to throttle positioner and altitude adjuste |
|
|
Thanks for posting this and the Bay porn that came with it!! 
Matt |
|
| Back to top |
|
|
airschooled
Air-Schooled
Joined: April 04, 2012
Posts: 12727
Location: on a bike ride somewhere
|
| Posted: Thu Nov 12, 2015 2:14 pm Post subject: Re: Introduction to throttle positioner and altitude adjuste |
|
|
| Alpha_Maverick wrote: |
| I assume you mean OTHER than making it easier to get the engine out of the car? |
That's one benefit of the one-piece positioners, but the two-piece style are functionally superior. Anyone? Bueller? Colin also pointed out to me that the two-piece positioner uses entirely filtered air. The one-piece positioner has the vent hole to the atmosphere. In some way that could shorten the life of the bellows by allowing dirt in, but it could also, maybe in the event of failure, allow unfiltered air into the engine intake.
Thanks for the kind words, Matt!
Robbie
_________________
Learn how your vintage VW works. And why it doesn't!
One-on-one tech help for your Volkswagen:
www.airschooled.com |
|
| Back to top |
|
|
Alpha_Maverick
Samba Member
Joined: May 01, 2011
Posts: 626
|
| Posted: Fri Nov 13, 2015 11:16 am Post subject: Re: Introduction to throttle positioner and altitude adjuste |
|
|
Looking at the diagrams, the only functional difference I can see between the one-piece and two-piece positioners is the presence or lack of the hose going to the carburetor. After inspecting pictures (I only have a 30PICT2, not a 30PICT3 or 34PICT3), my best guess is that this vacuum line applies vacuum to the top of the idle fuel well (above the fuel level) to decrease the pressure drop across the transition ports, thus significantly leaning out the air-fuel mix during decel.
That's my best guess.
_________________
| Alstrup wrote: |
| hmm well, wiggly I like 5,5inchers in the rear at least. |
|
|
| Back to top |
|
|
wcfvw69 
Samba Purist
Joined: June 10, 2004
Posts: 13389
Location: Arizona
|
| Posted: Fri Nov 13, 2015 3:34 pm Post subject: Re: Introduction to throttle positioner and altitude adjuste |
|
|
I was looking for the two piece throttle positioner for my 70' bus at a recent PHX VW show swap meet. I picked up an original used, Solex 34-3 with the attachment on the carb with the two nipples. I didn't notice until I was home that the linkage where it hooks up to the second accelerator arm was different. The one piece on my 69 has the ball and socket. On this 34-3 it has a hole in that arm and a pin goes thru it vs. the ball and socket.
I'm not sure if that the only difference though.
_________________
Contact me at [email protected]
Follow me on instagram @sparxwerksllc
Decades of VW and VW parts restoration experience.
The Samba member since 2004.
**Now rebuilding throttle bodies for VW's and Porsche's**
**Restored German Bosch distributors for sale or I can restore yours**
**Restored German Pierburg fuel pumps for sale or I can restore yours**
**Restored Porsche fuel pumps or I can restore yours**
**Restored Porsche distributors or I can restore yours** |
|
| Back to top |
|
|
airschooled
Air-Schooled
Joined: April 04, 2012
Posts: 12727
Location: on a bike ride somewhere
|
| Posted: Sat Nov 14, 2015 12:38 am Post subject: Re: Introduction to throttle positioner and altitude adjuste |
|
|
| Alpha_Maverick wrote: |
Looking at the diagrams, the only functional difference I can see between the one-piece and two-piece positioners is the presence or lack of the hose going to the carburetor. After inspecting pictures (I only have a 30PICT2, not a 30PICT3 or 34PICT3), my best guess is that this vacuum line applies vacuum to the top of the idle fuel well (above the fuel level) to decrease the pressure drop across the transition ports, thus significantly leaning out the air-fuel mix during decel.
That's my best guess. |
Interesting thought about the pressure drop across transition ports.
 My biggest observation this far, is the split second it takes to build "full" manifold vacuum during throttle closing. You can see this in wcfvw69's video, where the instant he lets the throttle shut, it snaps 100% closed for a click, then the positioner holds the throttle open the correct amount. Pay attention of you'll miss it!
You'll see that a working two-piece positioner does not have this delay. I think this is a key moment in cleaning up tailpipe emissions; especially if you consider how quick you'll let off the throttle if you get cut off by a Prius merging onto the freeway at 47mph. The two-piece positioner uses a modified ported vacuum nipple to slow or hold (I can't tell which yet) the throttle arm until manifold vacuum is enough to trigger the diaphragm and secure the arm in the open position.
| wcfvw69 wrote: |
I was looking for the two piece throttle positioner for my 70' bus at a recent PHX VW show swap meet. I picked up an original used, Solex 34-3 with the attachment on the carb with the two nipples. I didn't notice until I was home that the linkage where it hooks up to the second accelerator arm was different. The one piece on my 69 has the ball and socket. On this 34-3 it has a hole in that arm and a pin goes thru it vs. the ball and socket.
I'm not sure if that the only difference though. |
Bill, could you post a picture? I bought all the positioners I could from The Bus Co two years ago, and all of them had ball/socket connections. There were plates that fit the 34 and 30 series carbs, and none of them had a "cheap" linkage like that. This does bring me to another point though, in another thread somebody asked about bugs through '75 having the positioners too. I do not know what happened to the bugs after '71, since I only track the bus systems, which got dual carbs with dashpots, and later received Afterburner Heat Factories.
Robbie
_________________
Learn how your vintage VW works. And why it doesn't!
One-on-one tech help for your Volkswagen:
www.airschooled.com |
|
| Back to top |
|
|
mcdonaldneal
Samba Member
Joined: June 13, 2013
Posts: 2649
Location: Gullane, Scotland
|
| Posted: Sat Nov 14, 2015 1:58 am Post subject: Adjusting throttle valve positioner |
|
|
I've copied this post from our 1970 Ghia resto thread, it describes adjusting the two piece positioner, with pics...
Speaking of tinkering, after the basic tuning steps the Bentley gives instructions for setting up the throttle positioner/ altitude adjuster. I've never known how to get this working so I thought I'd give it a go.
The throttle positioner is attached to the carb. There is a lever inboard of the throttle arm which is attached by a threaded rod to a diaphragm unit that stares out at you as you look in at the engine. There is an adjustment screw to limit the travel of the lever, (black, directly above the threaded rod in the pics), and two vacuum lines on the diaphragm unit, one to the carb and one to the altitude adjuster next to the voltage regulator.
Bentley says to pull the lever against the adjusting screw to check the fast idle speed, and adjust this to 1700rpm. Mine had been disabled by extending the threaded rod to force the lever against the carb, so it wouldn't move. I loosened the locknuts and experimented with changing the rod length. Spinning it clockwise shortens it and stops the lever contacting the carb body. Spinning it anticlockwise lengthens it and stops it from touching the adjustment screw.
At this stage it worked well to unscrew the big screw on the altitude adjuster, which is the setting that does not slow the return to idle.
Bentley says adjust the rod length so that, at idle, the lever is not touching either the carb body, or the normal throttle lever (where the throttle cable attaches). My experience was that if the rod was too short, both levers got stuck and wouldn't return to idle (with the engine running). As the pic below shows...
Turning the rod anticlockwise at this stage suddenly got to a point where the levers sprung back to idle. This seemed the best length.
Having done that, the return to idle speed from 3000rpm is still quick, as the altitude adjuster is unscrewed. If you turn the screw in you get to a point where it will slow the return to idle to about 3-5secs (I needed about 4-5 turns).
After all that I took a test drive, and you can tell the difference in a slower return to idle. Is it any use? No idea! But it did help with double declutching from 4th to 3rd and 3rd to 2nd as you approach a sharp bend, holding the revs up. (Nobody does this any more, and the car will shift down without it, but it is kinder on the engine/ transmission!)
How's that for some useless information?!
_________________
1978 marino yellow Bay Dormobile camper
1969 signal orange Karmann Ghia convertible
1976 martini olive Bay Dormobile camper
Stop dead photo links! Post photos to The Samba Gallery! |
|
| Back to top |
|
|
mattlockwood
Samba Member
Joined: June 15, 2012
Posts: 360
Location: KCMO
|
| Posted: Sat Nov 14, 2015 8:32 am Post subject: |
|
|
| Tcash wrote: |
Thanks to jerseylooker
|
Thanks for posting this.
I see that the altitude compensator Fetzer valve (#9) has a hose that connects to a port on the intake manifold? My SP manifold doesnt have that, I dont think.... |
|
| Back to top |
|
|
airschooled
Air-Schooled
Joined: April 04, 2012
Posts: 12727
Location: on a bike ride somewhere
|
| Posted: Sat Nov 14, 2015 9:59 am Post subject: Re: Introduction to throttle positioner and altitude adjuste |
|
|
There were several different intake manifolds over the years, depending on vehicle type, emissions options, and weather or not you had an auto stick. Any vacuum nipple will work on the intake manifold for the signal line, weather it's just below the carb, or right next to either cylinder head gasket. The volume of air required to operate these devices is minimal, so it's not like a power brake vacuum line where a good jab on the brakes could alter the air/fuel ratio at idle.
Check around the left side (#s 3 and 4) cylinder head. Some early 1300 or 1500 engines might not have any vacuum ports, and who knows what parts are original anymore on these cars...
Robbie
_________________
Learn how your vintage VW works. And why it doesn't!
One-on-one tech help for your Volkswagen:
www.airschooled.com |
|
| Back to top |
|
|
mcdonaldneal
Samba Member
Joined: June 13, 2013
Posts: 2649
Location: Gullane, Scotland
|
|
| Back to top |
|
|
wcfvw69
Samba Purist
Joined: June 10, 2004
Posts: 13389
Location: Arizona
|
| Posted: Sat Nov 14, 2015 10:25 am Post subject: Re: Introduction to throttle positioner and altitude adjuste |
|
|
Mattlock,
These one piece idle positioners were installed on 68-69 bugs, buses and Karman Ghia's. There's ton of used carb intake manifolds out there for sale for these years. Just look for the one with the nipple on them. The other option besides Robbie's idea is to remove your intake manifold and drill a hole in it in the same location and weld the same diameter pipe in the manifold.
_________________
Contact me at [email protected]
Follow me on instagram @sparxwerksllc
Decades of VW and VW parts restoration experience.
The Samba member since 2004.
**Now rebuilding throttle bodies for VW's and Porsche's**
**Restored German Bosch distributors for sale or I can restore yours**
**Restored German Pierburg fuel pumps for sale or I can restore yours**
**Restored Porsche fuel pumps or I can restore yours**
**Restored Porsche distributors or I can restore yours** |
|
| Back to top |
|
|
Tcash
Samba Member
Joined: July 20, 2011
Posts: 12844
Location: San Jose, California, USA
|
| Posted: Sat Nov 14, 2015 10:33 am Post subject: Re: Adjusting throttle valve positioner |
|
|
Nice write up. I edited so members would not get the levers confused and put in the 68-71 bus specifications. Any changes required let me know?
Thank you
Tcash
| mcdonaldneal wrote: |
I've copied this post from our 1970 Ghia resto thread, it describes adjusting the two piece throttle valve positioner, with pics...
Speaking of tinkering, after the basic tuning steps the Bentley gives instructions for setting up the throttle positioner / altitude adjuster. I've never known how to get this working so I thought I'd give it a go.
The throttle valve positioner diaphragm unit is attached to the carb. There is a fast idle lever inboard of the throttle valve lever which is attached by a threaded rod with two lock nuts to the diaphragm unit that stares out at you as you look in at the engine. There is an adjustment stop screw to limit the travel of the fast idle lever, (black, directly above the threaded rod in the pics), and two vacuum lines on the diaphragm unit, one to the carb and one to the altitude adjuster (corrector) next to the (left tail light) voltage regulator.
Bentley says to pull the fast idle lever against the adjusting stop screw to check the fast idle speed, and adjust this to 1450-1650rpm not to exceed 1700rpm after a warn up drive.
Mine had been disabled by extending the threaded rod on the diaphragm unit to force the fast idle lever against the carb, so it wouldn't move. I loosened the two diaphragm unit lock nuts and experimented with changing the rod length. Spinning it clockwise shortens it and stops the fast idle lever contacting the carb body.
Spinning it anticlockwise lengthens it and stops the fast idle lever contacting the stop screw.
At this stage it worked well to unscrew the big screw on the altitude corrector, which is the setting that does not slow the return to idle.
Bentley says to adjust the diaphragm unit rod length so that, at idle, the lever is not touching either the carb body, or the normal throttle lever (where the throttle cable attaches). My experience was that if the rod was too short, both levers got stuck and wouldn't return to idle (with the engine running). As the pic below shows...
Turning the diaphragm unit rod anticlockwise at this stage suddenly got to a point where the levers sprung back to idle. This seemed the best length.
Having done that, the return to idle speed from 3000rpm is still quick, as the altitude corrector is unscrewed. If you turn the screw in you get to a point where it will slow the return to idle to about 2.5-4.5 seconds not to exceed 6 seconds after warm up drive 3-5secs (I needed about 4-5 turns).
After all that I took a test drive, and you can tell the difference in a slower return to idle. Is it any use? No idea! But it did help with double declutching from 4th to 3rd and 3rd to 2nd as you approach a sharp bend, holding the revs up. (Nobody does this any more, and the car will shift down without it, but it is kinder on the engine/ transmission!)
How's that for some useless information?! |
|
|
| Back to top |
|
|
mcdonaldneal
Samba Member
Joined: June 13, 2013
Posts: 2649
Location: Gullane, Scotland
|
|
| Back to top |
|
|
wcfvw69
Samba Purist
Joined: June 10, 2004
Posts: 13389
Location: Arizona
|
| Posted: Sat Nov 14, 2015 11:23 am Post subject: Re: Introduction to throttle positioner and altitude adjuste |
|
|
Here are the pictures of the throttle positioner bracket with the pin attachment to the throttle fast idle lever.
I wasn't aware of the difference between the 1971 Bus engine dual port 34-3 idle positioners and later bugs. I found this Solex 34-3 carb at last weeks VW bug show and swap meet. This 34-3 has a flange base number of 377 which identifies it as a 1973 carb mounted on bug engines. The seller also had the spare bracket as well. I didn't notice how it mounted when I bought it.
_________________
Contact me at [email protected]
Follow me on instagram @sparxwerksllc
Decades of VW and VW parts restoration experience.
The Samba member since 2004.
**Now rebuilding throttle bodies for VW's and Porsche's**
**Restored German Bosch distributors for sale or I can restore yours**
**Restored German Pierburg fuel pumps for sale or I can restore yours**
**Restored Porsche fuel pumps or I can restore yours**
**Restored Porsche distributors or I can restore yours** |
|
| Back to top |
|
|
mattlockwood
Samba Member
Joined: June 15, 2012
Posts: 360
Location: KCMO
|
| Posted: Sat Nov 14, 2015 11:32 am Post subject: Re: Introduction to throttle positioner and altitude adjuste |
|
|
| asiab3 wrote: |
| There were several different intake manifolds over the years, depending on vehicle type, emissions options, and weather or not you had an auto stick. Any vacuum nipple will work on the intake manifold for the signal line, weather it's just below the carb, or right next to either cylinder head gasket. The volume of air required to operate these devices is minimal, so it's not like a power brake vacuum line where a good jab on the brakes could alter the air/fuel ratio at idle |
Mine def doesn't have one, and my welding skills are tack weld rudimentary....
But there is this nipple on the doghouse, which is off a 74 beetle, for what, I do not know... Will this work? Diameter seems too large...
|
|
| Back to top |
|
|
|
