Carburater Vacuum lines

[rkieckhefer]

I had the carburater rebuilt on my 76 Cadillac Eldorado.  Front wheel drive, Rochester 4 barrel.  The vehicle still runs a little rough.  I'm wondering if anybody can provide a vacuum line schematic.  I've tried GM and their publishing company, Helm Publications to no avail. 
Please provide a link or feel free to email me a copy.
Thanks, Rick

[Caddyjack]

I'm not sure this will be easy to read, but it's worth a shot. Vacuum schematic from my 1976 shop manual...

[Jeff Maltby 4194]

This Help ?

[Scot Minesinger]

The shop manuals on e-bay are inexpensive and worth the weight in gold, highly suggest buying one for the vacuum diagram and many other items.  Those carb re-builds are never that good that they smooth out a rough idle.  Best of luck.

[cadillacmike68]

There was an older self starter article on these blocks (472 and 500) which detailed why these cars need a Lot of fuel to idle smoothly. the phenomena was called "Nozzle Drip" and the basic solution was to open up the mixture screws, which may or may not exist on a 1971 or later car. They were supposedly capped, but that was an emissions BS move and should be able to be undone.

Of course this won't help much if there is a vacuum leak somewhere.

[Aaron Hudacky]

The idle mixture screws were capped starting in 1979; but they can be drilled and adjusted.  Mine needed this to pass CA emissions in 2005, and once it was "clean", it idled noticeable smoother. 

[Scot Minesinger]

Plus those carb re-builds are often frought with work that results in not smooth idle.  I would say that for me one in three re-builds idle nice.  My car is good otherwise and I'm planning to get the carb-rebuilt by a better company re-bushing shafts and all.

[cadillacmike68]

Agreed, Scott. the first rebuild on my 1968's QuadraJet suffered from lean stumble. After someone who was better at it got done, that's gone, but I think it's running a bit lean, so we'll get to it with the tach / dwell and timer when i get back home.