Location

Closer

Closest I could get.
When I bought this 1981 Delta 88 307, this is what the idle mixture screw looked like; the counterpart looked the same.
I’m not extemely familiar with Qjets, so I took it to a local mechanic to have the carb adjusted.
When I got it back, both of these “screws” are gone, and the shop told me I need a new carburetor, because this one has already been rebuilt. They also told me I needed new belts even though I changed the belts not 5 days earlier; it’s a 307 with a belt squeal, something I stupidly thought a mechanic would know about.

I’m completely justified in calling this shop out, correct?

 

Carbs can be rebuilt any number of times, until sealing surfaces have deteriorated or warped or other parts have worn. Looks like they popped out the sealed idle screw plugs that electronic QJets came with and don't know how to correctly set this carb up. Joe Padavano is our site guru on these carbs. If he tells you the carb is junk, believe him. But he understands and knows how to work magic on these things.

Belt squeal on a 307 is a known quantity and the ones I've had it was usually the alternator belt, sometimes AC belt. You need a belt spreader tool to properly set tension on these. Sometimes seems to be worse on engines that ac belt has been removed.

 

My a/c belt has been removed, and I suspected that it was a factor in the squeal. This is next on my list, but not my priority currently.

You say it looks like they “popped out the sealed idle screw plugs and don’t know how to put it back together”, so they told me I need a new carburetor?

 

Yup. Good luck finding one 40 years after the fact. An electronic QJet is no worse to disassemble, clean and reassemble than a non-electronic carb but does require a couple of special tools and some electrical knowledge. I suspect this shop just doesn't want to fool with it.

 

I'd be looking for another shop that has specific knowledge about the CCC system Computer Command Control. The mixture screws were sealed by metal caps that had to be removed to adjust the idle mixture. From the pictures it looks as though they are in place. They should have a double d shape which requires a special tool to adjust them.

Carbs can be "rebuilt" repeatedly unless something is broken. The absolute worst thing that can be done to these carbs is allowing someone to work on them that doesn't understand them. You are better off in doing nothing to the carb than fiddling with it. When properly set up they run well.

What is wrong with this one that makes you suspect it needs a rebuild?

Good luck!!!

 

I'm not sure exactly what I'm looking at there, but these carbs came with an "anti-tamper" plug over the screw from the factory. You need to remove the carb to extract the plug before you can adjust the screws. These anti-tamper caps are probably a good thing for most people, because unless you read the Chassis Service Manual and follow the adjustment process EXACTLY, you will likely make things worse if you try to adjust those screws. This isn't like a pre-computer carb where you adjust the idle mixture with a vacuum gauge. The CCC system requires you to adjust the screws under a specific operating condition while monitoring the duty cycle of the computer-controlled mixture control solenoid inside the carb. Before you can do that, you need to be sure that every single vacuum line and external vacuum-controlled component is connected properly and operating. Try to take any shortcuts and you'll just end up chasing your tail.

 

Not really , it's just the wrong shop .
Very few mechanics under age 50 will have any experience with carburetors .
Try to find an " old timer " .

 

Few mechanics of any age have the experience or patience to properly adjust the CCC system. Keep in mind that this was a "band aid" to transition from carburetors to EFI, and was only used on a few models for a few years. The last such system was built in 1990 and very few remain on the roads now. The skills and tools needed to properly rebuild and adjust that carb are long gone from the general repair industry.

 

I know this is not a simple solution either, but the Holley Sniper Quadrajet is an alternative. And the distributor would have to be replaced too.
It is a real tedious job to work on that CCC system.

 

I can't say I'd use the word "tedious". It does require one to read and follow the CSM and pay attention to details. One problem is that these systems are 30-40 years old, and besides the obvious cracked and leaking vacuum lines, often the sensors and actuators in the system go bad. Correctly maintained and properly tuned, it works very well for what it was designed for. The CCC system is by no means a performance induction system.

 

Thanks everyone, especially Joe and SugarBear;

For a bit of an update, the shop didn't adjust anything but the idle screws on the carburetor, the picture I had posted was how the carburetor looked before bringing it in. I managed to use an older iPhone I had that was a bit smaller and could get into the angle I needed and was able to see the "double D" adjustment screws set about an inch inside. Admittedly, I'm new to carburetors, and learning on a (what seems like) rare ccm quadrajet that was only used until EFI came into common place. I'm glad I asked and took some time to get your replies before I went and lit up some mechanics that didn't deserve it and probably would have called me out on it.

I didn't want to go messing with the carb, so I did what I could without taking it off. I cleaned and lubricated the carb as best I could with it still attached, and changed the fuel filter. It started up great and sounded much better than before, I noticed the previous fuel filter was definitely due to be changed so I felt good. Then I noticed it was hot as heck on the driver's side of the engine; especially around the dipstick. I suspected the water pump, and once I read a bit more on some of the posts here, decided to check/change the thermostat. Once I got it changed I did the boiling water test and it opened at 205f (rated at 190f) then didn't open again when I put it back into boiling water. I replaced it with a lower rated thermostat.

I'm hoping this will get it on the road until I can get some of the other older vital organs replaced.

Thanks again for everyone's help!