Itinerant Air-Cooled

Hi.
Non of your carbs has the thermostatic valve I'm talking about. I have a pic off the 1969-1979 VW Bus official service manual pg 116 (unfortunately all attempts to attach the pic are failing- picture too large...I'll keep trying).

In regards to the retard port, are you able to indicate the port? On my left carb, I don't have a second port- the only one I have is just the same as what I see in the pics you've posted.

I've tried tuning my engine as you mentioned... a little high on rpm and I've noticed it's like the central-idle-circuit is redundant as even if I block the air passage, the engine doesn't die as it would earlier... I guess I'm running the engine on the carbs like it would be "independent carbs" (minus the central-idle-circuit). I hope that will give me a better drive for now-...as I wait for clarification on matters regarding retard (port on the carb).

I do appreciate the assistance offered.

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That carb has the thing... it is the item that is next to the accelerator pump, at the same place you would get the overflow nut/bolt.

The retard port is in the throttle plate of the left carb.

Go here: Ratwell's Baywindow site (https://ratwell.com/technical/DualCarbs.html). He has an excellent slide show on rebuilding and tuning PDSIT carbs. Many of your questions are answered there. Most of his photos are of the left hand carb and show a brass nipple in the throttle plate. That is the retard port. If you don't have a vacuum retard on your distributor, this nipple should be blocked off with a rubber cap.

Are you talking about the big brass plug (what Bentley calls the main jet cover plug)? That has no function on our engines other than just being a simple plug in the bottom of the float bowl and a way to access the main jet without taking the carb apart.

Satchmo

Hi.
Thanks for the ratwel link. I'll go through the page(s) and gather as much info.

On what I'm referring to, it is a valve just next to that big brass nut. It opens on temperature change which is on engine heating. It's opening is to reliev plenty of flow of fuel into the accelerator pump so as to reduce the volume of fuel sprayed. Well, I won't bother with that for now as I don't even know where I can get a replacement for the parts.
My drive on the carbs as independent units was different- a little better but will keep at it tomorrow. Thanks for the assistance.

ktk833 wrote: ↑

Mon Dec 20, 2021 10:46 am

Hi.
Thanks for the ratwel link. I'll go through the page(s) and gather as much info.

On what I'm referring to, it is a valve just next to that big brass nut. It opens on temperature change which is on engine heating. It's opening is to reliev plenty of flow of fuel into the accelerator pump so as to reduce the volume of fuel sprayed. Well, I won't bother with that for now as I don't even know where I can get a replacement for the parts.
My drive on the carbs as independent units was different- a little better but will keep at it tomorrow. Thanks for the assistance.

The temperature bias for the accelerator pumps on later engines does not affect our tuning process.
Colin