Dual carb settings

14platoon · Posted: Tue Nov 18, 2014 12:55 pm Post subject: Dual carb settings

1974 1800cc type 2 bay window on dual carbs

Does anyone know the base settings of the carbs to get them to a starting point?

Thanks

jfats808 · Posted: Tue Nov 18, 2014 1:25 pm Post subject:

If we knew what carbs you got along with complete specs of all jets, vents and altitude we can start to make recommendations. Eliminate the guess work and tell us all you know or post pictures.
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2276 IDA's 86C 11-1 DD !
2017 48 Trijet DRLA's W125

14platoon · Posted: Tue Nov 18, 2014 2:57 pm Post subject:

All I know is its a standard set up for an 1800cc engine with dual carbs
Solex and here's a rubbish picture of the left carb that I have to hand. I would not have a clue what jet sizes, recent purchase.
I thought there would be a base level to get started with.

Image may have been reduced in size. Click image to view fullscreen.

HRVW · Posted: Tue Nov 18, 2014 3:48 pm Post subject:

That small housing with the slotted screw sitting inside is your mixture screw. You would need a short small screwdriver coming into that housing from the front (Carb) towards you when adjusting it. The right Carb also has the same type of screw and adjusting it towards you....hard on the wrist and finger tips.

Tight area over a hot engine be it from under the rear tailgate or from the inside lid being open. I hated working on them 1.7 or the 1.8 same thing

14platoon · Posted: Tue Nov 18, 2014 4:08 pm Post subject:

I turned the mixture screws on both carbs in all the way and then out two and a half turns. When I tried to get the idle adjustment screw (big one on top) I couldn't bring the idle down far enough, this screw turned completely in to a stop and the idle was 1020. The volume screw on the top made no difference either.
I am having problems with a misfire so wanted to get the carbs back to a basic setting and work on from there.

HRVW · Posted: Tue Nov 18, 2014 5:39 pm Post subject:

You need to dis connect the linkage from one Carb and then SYNCH them after setting the timing......

1800cc 10 degrees ATDC at 950 RPM

14platoon · Posted: Tue Nov 18, 2014 10:44 pm Post subject:

I synced the carbs, just need to know the base setting for the big idle speed screw and the idle mixture screw on top of the left carb as a starting point, for example how many turns out they both need for an initial setting to get started with.
Thanks

HRVW · Posted: Tue Nov 18, 2014 11:07 pm Post subject:

If you synch the Carbs then they should be drawing the same air intake and the top screw should be turned in until the 950 RPM is obtained or what idle speed you choose. The idle speed screws are not set in stone and will vary engine to engine so NO set number of turns is known to me.

Has been a while since I worked on the 73-4 T2 Vans and my memory is a little fuzzy. Do recall the synch and idle being important before trying to adjust that small mixture screw in that small housing as I've still got the tiny screwdrivers I used back then in my Snap On box.

EDIT: With the small mixture screw turn in until engine falters sand then back off 2 turns....repeat on other Carb....back to 1st Carb and then back off to 1-1/2 turns out and then the other Carb. This is meant to get the leanest adjustment for gas mileage possible.

Then blip the Carbs for a response and test drive. You can always back off 1/8 of a turn on each carb if the power seems low due to maybe the Carbs mixture is too lean....all a matter of time...at least it was for me.

14platoon · Posted: Wed Nov 19, 2014 9:27 am Post subject:

Okay I'll give that a go, thanks.
I tested the distributor for vacuum by sucking the pipe to see the plate move, I got a mouthful of petrol??? Basically petrol is leaking from the carb to distributor vacuum........why would it be doing that?

HRVW · Posted: Wed Nov 19, 2014 9:53 am Post subject:

Cheers, just noticed you are in the UK as I'm formally from Canada...in essence we are cousins of sorts eh.

Gas in the dist vac is not good as the dist hose is connected to a Carb vac port (or should be) are you sure it is to the correct vac nipple?

14platoon · Posted: Wed Nov 19, 2014 12:21 pm Post subject:

I believe so, I think it's the only one on the throat. I've since read that vw did a metal upright loop for this pipe, gravity would stop the fuel getting down to the distributor....not sure if it's true though.
Yes I'm in the UK getting rained on as usual.

Slow 1200 · Samba Member Joined: July 02, 2004 Posts: 2106

you might want to check this

http://www.thesamba.com/vw/forum/viewtopic.php?t=399195

14platoon · Posted: Thu Nov 20, 2014 10:43 am Post subject:

That is excellent thanks. Are there some diagrams missing off that post, the author gas referred to numbers on a diagram but I can't view it?


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