Weber 34DAT stalling when cold

[nenenaiad]

Hi,

No problems.I am working on the rear arch which will be replaced by a large panel, have found some other corrosion associated with it and looks like a sill replacement on the same side. All good fun.

With regard to your problem you have only the back screw and screw 3 to adjust. I would concentrate on screw 3.

When you come back to me over the weekend let me know if you got a complete carb - it looks to me as though the bimetallic spring housing is off your old solex. There is a mark on your solex housing and you should find that there are two marks on the body of the carb, one of which lines up with the line on the housing. Which marks are lined up ?

Cheers


Dave

[cubensis]

Ok, i have just had a fiddle, but i have decided to pay the £60 and get it done properly, i dont have a rev counter or a co2 tester so will never be able to do it properly anyway. I have unfortunatley made the running slightly worse ( it stalls alot easier) and dont want to go to the point of no return!

However thanks alot for your help with this, out of interest could you forward the manuals you where talking about for this carb as i have no documentation as the mechanic kept it.

The choke flap did fully close, however like i say i may aswell spend £60 and then its done long term properly. Like i say thanks for your guidance!

[nenenaiad]

Hi,

O.K. All understood. It's a pity you are not nearer as i would have suggested you drop in and we sort it.

Just some final thoughts for you.

(1) Was it set up correctly ? There are two marks mark on the bimetallic housing and the mark on the part with the cooling system pipes on it should be against the second mark, which is the mark nearer to the front of the van. This part can be simply rotated to line up the marks once the bolts are loosened, not removed. I am also assuming that the bimetallic strip was also located properly in a slit on the machanism.

(2) Looking at carb top. Choke flap closes completely once choke set by depressing accelerator. On attempted start, choke flap should open several mm when measured at the bottom of choke flap. Adjustment 3 controls how much the flap opens and it is this I found was critical.
If this gap is excessive then the throttle link is moved off the fast idle cam.

(3) Yes I will scan the Weber installation instruction sheet and forward it to your e-mail address. (Have I got this ?) You already have the mixture set up instructions, but there may be something within it that helps you.



Let me know what you find and how you go on.

Regards


Dave



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[Pootle]

Can I hijack this thread? I searched the forums for "34 DAT" but not "34DAT" so I've just asked something similar here: https://club8090.co.uk/forum/viewtopic.php?f=2&t=48260" onclick="window.open(this.href);return false;

Do my symptoms sound the same as yours?

nenenaiad in a previous post you said "... as you screw 3 in clockwise, vacuum is resisted more and therefore you would expect the cam to stay on its highest lobes and stay on fast idle. Turning screw 3 anti clockwise has the opposite effect ... Start off by uncrewing screw 3 by say 1 turn and see its effect". Won't unscrewing screw 3 REDUCE fast idle?

Many thanks

[cubensis]

Hopefully this thread can be gracefully transfered to you . Dont get me wrong all the advice recieved from nenenaiad was great but i just dont have the time to make these fine adjustments, wait a day or half a day then make another fine adjustment as we are going away on the 21st of this month and i can't be arsed with grief from g/f when the van won't start, or the van is revving really high. Shame though i wanted to solve this problem myself (with help!), anyway its booked in for saturday morning to sort. Hijack this thread with pleasure hopefully enough information can be compiled to start a Wiki on this as this seems to be the main choice of carb to replace solex/peireberg and it'd be good to have a few troubleshooting threads with answers. Just for the record to anyone in the future, about £100 to rejet the carb (does this sound alot?).

Thanks again nenenaiad!

[Pootle]

hopefully enough information can be compiled to start a Wiki on this as this seems to be the main choice of carb to replace solex/peireberg and it'd be good to have a few troubleshooting threads with answers.

I've got an album of photos of a shiny new Weber 34DAT in various states of undress (including the installation instructions): http://smg.photobucket.com/albums/v75/Pootle/WeberCarb

Just for the record to anyone in the future, about £100 to rejet the carb (does this sound alot?).

It didn't sound like a jetting problem - did rejetting fix it?

[cubensis]

Ok heres probably my final bit of input on this topic! Went to get the carb sorted today, left it with the guy, an hour later he rang back telling me there was numerous things wrong, timing way wrong, vacuum hoses all connected wrong and carb needed stripping.

He agreed that every time the engine was switched of there was no consistancy when restarting, which is what i thought, id start it cold and it'd be fine, then id start it cold the next day and it'd stall, anyway as he puts it its 95% right. Dont quite know what he did because he was talking to me like i'd been a mechanic for the last 10 years when in fact i have very little mechanical knowledge, so my eyes glazed and my head started nodding about a minute into him talking, one thiing i did catch though was the fact that my distributor is one with vacuum hose connections, and apparently this weber doesnt need this to work, he's took the vacuum hose of the dizzy completley (as well as reconnecting the other hoses in the right order! (not my fault!)).

Ok ... only thing is! It now idles alot lot better but ... seems like alot less power, went up a hill to join the motor way pn the way home from Bury and couldn't get over 40, im sure it would have slowly accelerated up the hill before, is this normal? Will be ringing him back on monday to see what he has to say just thought id post my results here.

[Pootle]

one thiing i did catch though was the fact that my distributor is one with vacuum hose connections, and apparently this weber doesnt need this to work, he's took the vacuum hose of the dizzy completley

I've never heard that before. The need for timing advance isn't directly related to the carb.

seems like alot less power, went up a hill to join the motor way pn the way home from Bury and couldn't get over 40, im sure it would have slowly accelerated up the hill before, is this normal?

That's exactly what I'd expect if the vacuum advance had been taken off the dizzy - poor acceleration.

If you look in my album here: http://smg.photobucket.com/albums/v75/Pootle/WeberCarb" onclick="window.open(this.href);return false; and click on "Complete 04" I've highlighted the Vac advance connection. You could replace it and see how it affects performance.

[cubensis]

Only goes up to "complete 03" mate! Will definatley have a look when its there though, i rand him explaining there was less power at the top end (3rd/4th) he was suprised but cooperative with it, its going back in on Thursday, he told me power on the rolling road was fine at around 60HP, see what happens on Thursday!

[Pootle]

Only goes up to "complete 03" mate!

Whoops ... Complete 04 is there now!

he told me power on the rolling road was fine at around 60HP

60HP at the wheels? What engine have you got? Standard DG? Did he give you a graph? I ask because I put my van on a rolling road a couple of years ago and got 48 BHP at the wheels.

[cubensis]

Hiya, no didn't get a graph, he just mentioned 60HP on the rolling road. Its a 1.9DG, so 60HP seems pretty good yea?

Thanks for putting "complete 04" up, The vac advance you have labelled has been terminated on mine (screw put into vac hose). You say this would make top end speed sluggish?

[Pootle]

Hiya, no didn't get a graph, he just mentioned 60HP on the rolling road. Its a 1.9DG, so 60HP seems pretty good yea?

I would say so, yes!

You say this would make top end speed sluggish?

It would kill your acceleration. You should still be able to reach the same top speed, but it will take a lot longer.