Pierburg 2E3 cold start

[charlie328]

Hello,
Looking for a bit of detailed knowledge really. My van has become difficult to start from cold and it is due to the choke flap not closing when you depress the accelerator. I have checked the linkage and it just seems that I have a part missing between the throttle input and the choke flap bell-crank? What mechanically pushes the flap closed? Have looked around the forums and cannot find a decent close-up photo of the linkage as installed on a T25 2E3 hence my appeal to greater knowledge.
Any help appreciated.

[CJH]

You may be missing the white plastic part in this photo:



It seems that they split then fall out - quite a common failure apparently. Unfortunately you can only really check whether it's there by looking from underneath on the choke side. It's easy to see if you separate the top and bottom halves of the carb, which is how I took the photo above.

If you're missing this part I can supply them for £1 plus £1 postage. Development thread here if you're interested.

[charlie328]

Thanks for the photo. Yes please, let me know how to buy one of these from you. (Well done with the manufacturing process too).
Looking at the photo : is the choke flap on the pivot of the plastic part, as with my carb you can press the metal lever (at top of photo) and the choke flap moves.
Going to have to split the carb anyways so will replace the plastic part on spec.
Charlie

[CJH]

Looking at the photo : is the choke flap on the pivot of the plastic part, as with my carb you can press the metal lever (at top of photo) and the choke flap moves.

It sounds like you don't need the white plastic part in that case - yes, the spindle of the choke flap is the pivot of the plastic part, so if you can operate the choke flap by pressing the metal lever then I think your plastic part must be intact and working.

So what else could cause your choke flap to stay open? Good question. The stepped cam (for the fast idle) and the metal lever (for the choke flap) rely on the choke spring. This photo shows a rubber band taking the place of a cold choke spring - the white nylon lever gets pulled clockwise by the choke spring.



Here's one of Kev's photos:


The square loop in the outer end of the spring engages with that white nylon lever, and as the spring heats up it uncoils, pushing the nylon lever to the left (anticlockwise), which should open the choke flap and move the fast idle screw down the stepped cam. When the spring is cold is should push the lever clockwise to close the choke flap and put the fast idle screw on the higher steps of the cam.

So it's my guess that the shaped end of your choke spring isn't engaged with that white nylon lever.

[charlie328]

Thanks for the info.
My spring was wound on an extra turn and so holding the valve open. Flap now closes and chokes properly but action feels a little stiff.
Will see if it all resets nicely on next start.
Thanks again
Charlie