Adjusting the Quadrajet?

[Phoenyx]

OK, here's a new problem for me.

I'm in the process of tuning up the 305 in my Malibu. But for some reason I cant adjust the carb. I know about GM capping off the adjustment screws and mine are already uncapped (unless they weren't doing this yet on the '80 models). I bought the proper tool for it and it fits on. The problem is the screws won't turn. I tried on both sides, and they both seem to be stuck.

Has anyone ever heard of this? Is there something I am missing or don't know about?

 

[Phoenyx]

Well I sprayed some carb cleaner into where the adjustment screws are. Didn't make any difference. I was hoping it was just gummed up. Maybe after is soaks over night it will be better.

 

[dan2286]

Carb cleaner wont really "soak in". Try penetrating oil.

 

[85 Cutlass Brougham]

You may end up having to pull the carb to see why they are stuck. It may have been some evil on GM's part to keep you from tuning it. Also, is it an electronic carb or is your car equipped with either the C4 or CCC system of engine management? Being a 1980 model, it may have some "unusual" quirks to the carb.

 

[Phoenyx]

Will do. I think it's so weird that they are stuck like that. I have never heard of this happening before.

 

[srercrcr]

A GM service manual would clear up this issue real fast.

 

[mhamilton]

The 1980 were not yet computer (except CA). The screws have nothing special about them, but are likely rusted on the inside.

I'd advise against trying to mess with the idle mixture adjustments. You can turn those screws all day and you may not notice any change in the engine.

What likely happened was the throttle shaft wear allowed the idle mixture to go too lean, so someone backed the adjustment out. The problem is, with the shaft wear (guaranteed on the Rochester aluminum base plate) you will NEVER get the idle adjustment right.

 

[Phoenyx]

Well my '85 Bonneville has had the cc carb removed for a normal one. And it seems pretty good. Maybe I'll use that one.


Does anyone know a good site that I can check the numbers and see what kind of carb it is?

 

[mhamilton]

I don't know a web site, but if you post the model number I can look in the manual for you. The model numbers actually can be decoded somewhat like a VIN.

 

[Phoenyx]

Well I got the kids today so I probably won't get a chance to get the numbers until after supper. Where do I look?