yes it is the pull down unit
the unit uses the vacuum to open the second choke flap and keep it open. Or the choke return spring will shut it
if it is leaking air (which goes into the venturi) then it will close as you come off the throttle.
simple check, remove the pipe from the carb and suck air from the unit.
If you can, it's shagged.
Hesitation on light throttle
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kevtherev
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Re: Hesitation on light throttle
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CovKid
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Re: Hesitation on light throttle
If only they put it like that in Haynes Kev - save so much confusion. 
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humphry
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Re: Hesitation on light throttle
not wanting to preach to the chior 
but do you know that there is a small cone shaped fuel filter fitted inside the brass tube that the fuel line connects to on the carb details on tech n tips under two filters on fuel line.... 
ok having light the touch paper stand by for fireworks but i guessed some might not know 
but do you know that there is a small cone shaped fuel filter fitted inside the brass tube that the fuel line connects to on the carb details on tech n tips under two filters on fuel line.... ok having light the touch paper stand by for fireworks but i guessed some might not know -
ghost123uk
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Re: Hesitation on light throttle
humphry wrote:not wanting to preach to the chior
Well worth pointing out, but that would cause starvation under load and I think the problem here is a flat spot on trying to accelerate away, and then all is ok after that.
Has anyone mentioned checking the accelerator enrichment pump & jet above ^^^...? = Ahh, yes they have
pionte wrote:the accelerator pump is working and spraying in fuel and all jets looked clear.
Got a new van, but it's a 165bhp T4 [shock horror] Accurate LPG Station map here
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pionte
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Re: Hesitation on light throttle
Thanks for all the advice and input guys.....
The van is running much better now, this is what I did
Removed the carb, cleaned all the jets and checked operation of accelerator pump, rebuilt carb with kit from Brickwerks.
Replaced large vacuum pipe that goes from inlet manifold to somewhere unknown ! replaced small vacuum pipes from dizzy and air box, replaced oil breather pipe.
In hindsight the most probable cause of the problem was the disconnected vacuum pipe going to the air filter and the leaky vacuum advance to the distributor.
Mart.
The van is running much better now, this is what I did
Removed the carb, cleaned all the jets and checked operation of accelerator pump, rebuilt carb with kit from Brickwerks.
Replaced large vacuum pipe that goes from inlet manifold to somewhere unknown ! replaced small vacuum pipes from dizzy and air box, replaced oil breather pipe.
In hindsight the most probable cause of the problem was the disconnected vacuum pipe going to the air filter and the leaky vacuum advance to the distributor.
Mart.
2.5 Quad Cam Scooby engine . Westfalia California 1989
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ghost123uk
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Re: Hesitation on light throttle
Glad you got it sorted and thanks for posting the "fixed it" info for others to read.
The large Vac pipe from the inlet is the one that goes to your brake servo, so pretty important !
The large Vac pipe from the inlet is the one that goes to your brake servo, so pretty important !
Got a new van, but it's a 165bhp T4 [shock horror] Accurate LPG Station map here
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pionte
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Re: Hesitation on light throttle
Just a quick update,
I went down to the New Forest for the Bank Holiday weekend, approx 300 miles in total and the van ran Faultlessly
even hitting an indicated 90 at one stage 
So I am very pleased, I would highly recommend checking your vacuum pipes if you have any hesitation on light throttle.
I went down to the New Forest for the Bank Holiday weekend, approx 300 miles in total and the van ran Faultlessly
even hitting an indicated 90 at one stage So I am very pleased, I would highly recommend checking your vacuum pipes if you have any hesitation on light throttle.2.5 Quad Cam Scooby engine . Westfalia California 1989
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rustytop
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Re: Hesitation on light throttle
Good to hear that you've sorted it. I've only got as far as the vacuum pipe to the brake servo, the vacuum advance unit and the pipe between this and the carb. After a quick run it did seem that I'd cracked it, but alas since then I did another short trip around town, and at one junction (after waiting for a space) it seemed to have no power for 1-2 secs (as I applied throttle) but then picked up ok straight after.
One question, did you also get a slight hesitation when say going down hill (no throttle) then applying throttle to go up the next hill? Mine does this occasionally also.
One question, did you also get a slight hesitation when say going down hill (no throttle) then applying throttle to go up the next hill? Mine does this occasionally also.