So, what might the pros and cons be of installing the throttle positioner on the Wonderbus? I reckon that folks remove, typically. I gather that it was part of the original emissions control, seems to have some kind altitude compensation, too.
-- Mike "Rocket J Squirrel" Elliott
71 Type 2: the Wonderbus
84 Westphalia: "Mellow Yellow (The Electrical Banana)" KG6RCR
It's been so long since I worked on my old neighbor's '71 type 2 that I hardly remember the details. I do recall that the only way to get it to run right was to get ALL the parts working together. If you left out the throttle positioner then you would also have to either disconnect the vacuum retard or change the idle advance setting (or something like that.) I just put it all back to stock and it always worked really well.
I don't like changine the idle timing, because that changes the high speed timing, too, and that can be a bad thing. I've always emphasized long term reliability and I didn't want to do anything that someone would be sorry for 5 years down the road.
Yes, the purpose of the throttle positioner was to keep the throttle from slamming all the way shut on overrun, to prevent excessive unburned hydrocarbon emissions.
I THINK I may actually have one of the rebuild kits for the throttle positioner still downstairs. Need one?
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----------------------------------------------- Jim Adney snipped-for-privacy@vwtype3.org Madison, WI 53711 USA
I dunno -- the feedback I'm getting from some friends is that, yes, the throttle positioner was designed in as a means of getting rid of the unburned hydrocarbon "burp" (or fart) that occurs whenever the foot comes off the pedal and the spark is still advanced by letting the butterfly close more slowly. But (A) positioners age and stop working so good, sometimes tending to sort of keep the revs higher for longer than one might want, and (B) mounting a positioner to this carb (
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) may not be possible. I reckon that I'll just let this one slide. Thanks for the offer, though!
-- Mike "Rocket J Squirrel" Elliott
71 Type 2: the Wonderbus
84 Westphalia: "Mellow Yellow (The Electrical Banana)" KG6RCR
Beetles equipped with the 34 carb did not have the throttle positioner, and they worked fine. It is not needed for the engine to run right, and it missing would not cause the engine to stall. I've yanked those out before.
Nah, but finding out that as an emissions-reduction device the throttle positioner was an unreliable band-aid at best did.
Re-conditioning the e-can -- now /that/ is do-able and easy. I checked: blew into the fuel tank vent line and was greeted by a returning puff of pure gas fumes. Made my eyes water. That line is open. To the pet shop for charcoal!
-- Mike "Rocket J Squirrel" Elliott
71 Type 2: the Wonderbus
84 Westphalia: "Mellow Yellow (The Electrical Banana)" KG6RCR
I bought a used 34PICT3 from airspeed in excellent shape. It has the throttle positioner which is fully functional. It mounts to a bracket which is held onto the carb at two of the top plate assy screws. It just delays the throttle plate from slamming shut. It may be an emission device but I can see it improving shifts and maybe minimizing that issue you have with the stalling. VW shops usually have a boneyard box full of old carbs. Maybe you can get lucky.
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