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pierburg carb choke issue

Posted: 14 Mar 2015, 15:37
by bugsteve
hello all, can anyone advise on issue i am having... the mechanical side of the choke is working fine, butterfly closes when cold and opens when hot but from cold the revs do not rise to keep engine running.. I had carb rebuilt by bromyard sometime ago and everything was fine for a time. Ive since had it apart and checked everything.. all looks well regarding the springs and the general mechanism but problem persists. can anyone tell what the wire to the choke does and what voltages i should be looking for as maybe this is the issue?

thanks for reading

Re: pierburg carb choke issue

Posted: 14 Mar 2015, 15:50
by kevtherev
The fast idle mechanism is not electrical
you can adjust the fast idle mechanism.
when you start the van are you depressing the acc once fully before cranking with your foot off?

When you checked it did you operate the throttle and see the stepped cam turn?

Re: pierburg carb choke issue

Posted: 14 Mar 2015, 16:00
by bugsteve
yep.. always actuate choke before start.. will not start unless give some gas and will not tick over till warm.. stepped gear is making contact ok.. i operated carb on the bench and inspected... all seemed well.

Re: pierburg carb choke issue

Posted: 14 Mar 2015, 16:16
by MidLifeCrisis
Is the choke pulldown working correctly?

Re: pierburg carb choke issue

Posted: 14 Mar 2015, 16:22
by bugsteve
yes all vac jobbies working... but that is not for cold start on idle.. that is for when you put your foot down when cold.. it pulls off the choke to give better acceleration

Re: pierburg carb choke issue

Posted: 14 Mar 2015, 16:48
by kevtherev
Ok so the cam operates, you can undo the three screws and turn the autochoke housing clockwise about 5mm.
That should advance the cam.
mark the housing so you can return it.

Re: pierburg carb choke issue

Posted: 14 Mar 2015, 16:50
by kevtherev
bugsteve wrote: i operated carb on the bench and inspected... all seemed well.

did the cam flip to the highest step when you rotated the butterfly spindle fully?

Re: pierburg carb choke issue

Posted: 14 Mar 2015, 17:24
by MidLifeCrisis
bugsteve wrote:... but that is not for cold start on idle.. that is for when you put your foot down when cold.. it pulls off the choke to give better acceleration
Not sure I agree with that - see the below from Haynes Carb manual .... it should actuate immediately on engine start to slightly open the choke valve to weaken the mixture

Image

Re: pierburg carb choke issue

Posted: 14 Mar 2015, 17:45
by kevtherev
MidLifeCrisis wrote:
bugsteve wrote:... but that is not for cold start on idle.. that is for when you put your foot down when cold.. it pulls off the choke to give better acceleration
Not sure I agree with that - see the below from Haynes Carb manual .... it should actuate immediately on engine start to slightly open the choke valve to weaken the mixture

Image
Is that the 3mm gap setting at idle?
Yes I believe the pull down controls that setting

Re: pierburg carb choke issue

Posted: 14 Mar 2015, 17:49
by MidLifeCrisis
kevtherev wrote: Is that the 3mm gap setting at idle?
Yes I believe the pull down controls that setting
Yep

Re: pierburg carb choke issue

Posted: 16 Mar 2015, 19:41
by bugsteve
thank you all for your helpful replies, i was not able to recheck and problem solve yesterday as planned as it was hammering it down here in czech. better weather is here now and should remain over the weekend so i will get on it and report back!

Re: pierburg carb choke issue

Posted: 31 Oct 2015, 08:44
by ajsimmo
Blimey, this job's a slow burner! Be needing that choke working right soon.
How did the engine rebuild go?