HELP! 1985 1.9 wbx with 34 dat weber stalling after startup

[kevtherev]

I'm reading it as though it will also stall after 5-10 seconds if just left to idle after startup...!??

Yes me too, so the choke is coming off, and as it does so the mixture weakens to a point whereby it stalls

[Smiffo]

I'm reading it as though it will also stall after 5-10 seconds if just left to idle after startup...!??

Yes me too, so the choke is coming off, and as it does so the mixture weakens to a point whereby it stalls

I see. You will be far more familiar with all things T25 then me Kev.
What I have learned in part cam from your input ( and others. )

Please take this strictly as a question then - is 5-10 seconds a little early for the choke to start turning off?

Not suggesting you are wrong, just trying to fathom the details in my head

[kevtherev]

I can only speak from a pierburg experience but I would imagine the weber choke parameters are similar.
It takes around 6 mins for the choke to be fully off from ambient temps we are enjoying at the moment.
The choke has an electrical heater and starts its opening journey as soon as the engine starts.

[Simplymiles]

Ok so the there is a difference in the choke system as mine is not electrical but operated by the coolant heating up a bi-metallic spring as the engine heats up. Before that bi-metallic spring heats up the carb uses vacuum to operate the choke flap as it takes a little while for the coolant to warm up.

When i start up the engine i quickly run to the engine and can see that the vacuum appears to be operating the choke flap and the engine seems to run sweet but then all of a sudden it will just stall with or without any extra throttle. Which doesnt even give the coolant time to warm up enough to start operating the bi-metallic spring..

So i checked the jets again and the inlet filter, no problems there so i will check the timing in the morning but think i will also order a carb srvice kit just to eliminate any air leaks.

Really appreciate the help here guys, hopefully i can get it sussed soon

[kevtherev]

If the vacuum is opening the choke, have you tried disconnecting that function?
(block off the vac tube)
Delaying the choke will hopefully extend the warm up period

[Simplymiles]

As in to keep choke flap fully closed?

Ah ok see what you mean yea il give it a go

[kevtherev]

As in to keep choke flap fully closed?

Yes and just let the bi metallic spring open it with the coolant warming it

[Simplymiles]

Ok so cant quite do that as the vacuum is kind of built in the carb so the only way i can do it is to adjust the screw on the diaphragm to set how far open it comes so will try a few different settings and see what differences occur

[kevtherev]

Not a weber owner but any elimination of symptoms can only result in the correct diagnosis.

[Simplymiles]

You got it bud!

Plus it just helps discussing and going through options with another person as i had pretty much melted my brain trying to figure this all out.

[300CE]

I'm running a 34 DAT and had a problem with the van running properly after I rebuilt the carb and it was down to the mixture.

To test, what I would do is start the van as you are doing and then turn the mixture screw inwards (to the right) until the revs start to drop and then wind back out about half a turn. I've arrowed where this is in the pic below.

It may also be down to the vacuum advance hose and I'd be happy to send you a cut off from the hose I'm currently using just so you can rule this out - let me know!

[Simplymiles]

When you say vacuum advance hose which one are you talking about exactly? I guess you mean the hose running from the distributor...right?

[300CE]

Yep, from the dizzy to carb - the blue one in the pic

[Simplymiles]

Yea i have checked that and seems to hold pressure ok.

Also i notice that the solenoid on the front of your carb (which i guess is a fuel cut off solenoid?) has a wire connected, on mine that has never been connected to anything and the actual wire has been cut off right at the solenoid. Could this be an issue? Although the van used to run and like i say it has never been connected to anything and i dont have any spare wires laying about to connect it....

[300CE]

Yea i have checked that and seems to hold pressure ok.

Also i notice that the solenoid on the front of your carb (which i guess is a fuel cut off solenoid?) has a wire connected, on mine that has never been connected to anything and the actual wire has been cut off right at the solenoid. Could this be an issue? Although the van used to run and like i say it has never been connected to anything and i dont have any spare wires laying about to connect it....

Hmm, someone else maybe be best to answer the solenoid issue, but if I disconnect it on mine the van cuts out. I can take a pic and show you where it's connected to tomorrow?