Carb question !

[Hilly_70]

Hi guys ..

Just a silly question about vac advance and carb ..

34 pict 3, twin port , standard set up ..

My vac supply feeds from the manifold side .. but I wondered what the spare pipe was on the side of the carb .. I just found out from a picture for setting up carbs that this is the vac advance feed .. or at least it feeds from there on the set up pics ..

Should it run from the carb or manifold?

If manifold ( as it currently is.. ) should the one on the side of the carb be blocked off? .. cos mine isn't ...

Hope that makes sense!!

Cheers

Hilly

 

[Haveacamper]

i think that the take off from the manifold is usually for the brake servo. i know on dellorto carbs the vaccuum advance take off is on the carb.

i am not sure if there is a difference in vaccuum from manifold and carb

 

[Araon]

Throw up a pic fella but sure its the servo vac your using....

 

[Hilly_70]

Cheers mate ...

its connected here on the manifold..

with nothing here on the carb ..

more i look at it the more im sure its wrong .. if i reconnect it to the carb should i then just blank off the manifold with some tube ?

.. scary thing is its been like this for 2 years and i aint noticed! shows you what i know :?

cheers

hilly

 

[Araon]

yep your using the servo vac and the small tube on the carb is your vac advance

 

[Hilly_70]

Cheers mate .. How much difference does it make?

I only ask cos I just put where it should be, and blanked the servo one off and it doesn't seem to have made a lot of difference .. I haven't had it out on the road yet though... !

Thanks for the help mate!! .. owe you a beer ..

Hilly

 

[Clarkson46]

You may find that your idle mixrure is a little off as the vac take was not blanked off and the carb has been set up like that. It may pay to set everything up again including the timing.

 

[noddy]

Hi

You should be using the vacuum port on the carb, the manifold vacuum port is for the throttle damping system that was fitted to 69/70 buses to get over emission issues, servos weren't fitted till 71.

Please see bentley manuel fuel system section page 28.

If your running a 30 pict 3 carb there should be a second vacuum port on the front of the carb (rear of vehicle), this also connects to the throttle damper.

Hope this helps, would post picture but camera is bo***xed.

Ian

 

[Araon]

hes running a 34/3 on a twin port so its a 71 engine.... on the rear of the carb (infront of you looking into the bay) you'll have a retard vac pipe that will need to be blocked too.....

 

[Hilly_70]

Cheers guys ..

swapped the vac position .. sealed the servo vac .. reset carb .. went to Vikingvolks..

Extra 5mph cruising speed .. 100% better on hills ..

a happy man .... for now ..

Thanks again!

Hilly

 

[Guest]

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