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HI Mike,
What your describing is sort of normal ops for a Q jet. If you let these sit the gas in the bowl will evaporate and it takes some cranking to get the fuel pump to fill it enough to activate the accelerator pump circuit. If I let mine sit I have to crank it quite a bit to get it going.
it's normal to press the accelerator two or three times prior to starting these cars to set the choke and provide an accelerator pump charge.
The secondaries don't have an accelerator pump circuit, so nothing is going to squirt on them. The secondaries are mechanical, with an air flap on top that opens as the airflow increases, as it opens it allows more fuel to be fed into the secondary circuit. Hold the throttle open by hand and then take your finger and move that air flap open to see the secondary plates open at the bottom of the carb.
Lars (the go to Q jet carb guy here) has long said that the rebuilt Q jets by the commercial rebuilders are badly screwed up by them and often don't function as they should.... you should talk to him.
Your third picture looks like the accelerator linkage is in the wrong hole. It should be on the bottom one. That will get your secondaries to open.
Also, switch to manifold vacuum should help with the starting issue. That plugged tube by the choke apparatus should be manifold. Initial timing on my 69 350 is 12 degrees. Also, the proper fuel filter at carb with anti-siphon valve (NAPA has them) will help the cold start issue, too. (Might want to go with steel fuel line from pump to carb, too.)
As far as linkage adjustments go....the Rochestor QJet book is good at detailing the basic setup. While the book isn't specific to each Qjet model number inside a rebuild kit there's usually a sheet that details the specific linkage adjustments for each carb. There's a 'adjustment data table' which lists the measurements and n instruction sheet that details how to make the adjustments. I Googles around and count find them for your carb. Maybe you'll be able to find them. Might be worth the cost of a kit to get the tables/instructions.
From: At my Bar drinking and wrenching in Lafayette Colorado
You have a commercially rebuilt carb with dozens of problems and missing parts. You are also missing your entire choke linkage, which makes your choke system inoperable. You don't just have one problem - you have multiple problems, incorrect parts, and missing parts in that carb. It is not financially viable to rebuild, correct, or save. Find a good, used, original carb in un-modified condition and rebuild it to spec. If you'd like a list of all the likely problems with your carb, drop me an e-mail request for my "Commercially Rebuilt Q-Jet Problems" paper. The racing-type distributor without vacuum advance is not a good choice for a street car, and is compounding your carb problems. The secondary airvalve will not open by "winging" the throttle in neutral, and there is no accel pump on the secondary side. However, your secondary throttle linkage is WAY out of adjustment, and may prevent the secondaries from opening when the engine is running due to the linkage being unable to overcome engine vacuum to open the throttles.
From: At my Bar drinking and wrenching in Lafayette Colorado
If you want to maintain an original level of performance, you need to locate a good rebuildable Q-Jet 750 carb - you can e-mail me for info about how to go about doing that. If your car is too fast and you need to tone it down, step down to an Edelbrock so-called "Performer" carb (actually a re-pop of the old Carter AFB carbs, which were deemed obsolete by GM after the 1966 model year - we used to throw those carbs in the trash can back in the early '70s...). The Edelbrock carb will make your car run as smooth, powerful, and reliably as your aunt Edna's Caprice station wagon, which is not a bad choice for some people.
From: At my Bar drinking and wrenching in Lafayette Colorado
Originally Posted by 71 Green 454
Where's your choke spring?
Whoever pieced the car together couldn't install the choke system because they have installed a 1980 intake manifold. Notice the block-off pad for the EGR and the lack of holes for the hot air choke tubes (and no provision for divorced choke coil), which means it's an intake designed for an integral electric choke. Things aren't working because the parts are all mis-matched... Bubba put the engine together, and didn't care too much about finding the correct parts to make everything work right... It's Mike's job now to make it right...
Originally Posted by mike914
As far as the fuel leak I'm not understanding. Please advise. Mike
The fuel leak is not significant - you have some "wetting" and "wicking" of the airhorn gasket, which is a sign of high fuel level in the carb due to lack of fuel level control. This can be caused by several issues, all of which would be common and expected with that commercially built carb.
Whoever pieced the car together couldn't install the choke system because they have installed a 1980 intake manifold. Notice the block-off pad for the EGR and the lack of holes for the hot air choke tubes (and no provision for divorced choke coil), which means it's an intake designed for an integral electric choke. Things aren't working because the parts are all mis-matched...
Lars
Well that explains it....a real hodgepodge of components.
On another note, it amazes me Lars how you have the time to respond to threads and explain things in detail.
From: At my Bar drinking and wrenching in Lafayette Colorado
I'm "retired," and I have a computer with WIFI sitting right here on my workbench in the carb rebuilding area, so I have easy ability to make some quick responses to questions as they come up (whenever my WIFI is working...).
From: At my Bar drinking and wrenching in Lafayette Colorado
The real question for Mike is, "How do I fix this mess?"
There are a couple of options. The most desirable option is to make the car, and the engine compartment, look "visually correct." To do this, a 1968 intake manifold will need to be procured. However, if his engine really is the 350-hp 327 (L79), the intakes are unique (part number 3919803). But they are available on eBay and other sources for a few hundred bucks. This one is for sale right now for $170:
This manifold can be used with any 1968 - 1974 divorced choke Chevy passenger car carb for a visually "correct" appearance and with a great level of performance. The actual 1968 L79 Q-Jet carb cores are getting extremely expensive, so a "look-alike" alternative is probably a better solution.
If Mike wants to use the existing 1980+ intake manifold for a minimal amount of work and expense, you can procure and rebuild a 1976 - 1980 Chevy passenger car Q-Jet and convert it to electric choke. This will run very well, and will provide excellent performance, but it will not look visually "correct."
If a correct appearance is not important, a Holley 4165 or 4175 spreadbore carb with electric choke can also be used on the existing intake manifold. These carbs actually run pretty well, and would require only a few mods for installation.
Lastly, if the only intent is to get the car running in a reliable fashion, one of the Edelbrock carbs with a dual bolt pattern for Q-Jet intake manifolds can be used. These carbs do not match the airflow of the Q-Jet, and wil not perform as well as a properly set up Q-Jet, but it will get the car running. It would be a better setup than what he has...
Quadrajet Help please
