Carb Problem

[madisonguy]

Hey guys (and gals),

On an unrelated topic: my engine was making a crazy noise that sounded like really bad knocking or valve noise, but only above about 3000 RPM. It turns out it was a belt! That's the last thing I thought it could be. The noise was definitely more like a knock than a squeal. If you don't have an automotive stethoscope, run--don't walk--to your nearest auto parts store and buy one. It's worth its weight in gold.

--- now on to the real topic ---

Here's a problem that can't be solved with a stethoscope. I've got a quadrajet carb that won't choke. As far as I can tell, everything else works properly, including the accelerator pump. When you push the throttle to the floor, nothing happens to the choke. Cams turn and levers move (on the choke side of the carb), but none of that results in the choke actually being set. Every time I do a cold start I actually have to pop the hood and set the choke by hand.

Any ideas??? I know this is a real reach, but if anyone can think of anything, I'd really appreciate it.

Thanks,
John

[rage'nrat638]

post a picture of your choke side of carb.......we will tell you whats missing or whats incorrect......your pal mark

[madisonguy]

Good idea... My camera is pretty crappy, but maybe you can get an idea from the pics.



Thanks,
John

[4x4Poet]

If you retake the pics with the AC spacer off the carb, we, ...er, the board's resident carb experts could then see the position of the choke butterfly relative to the position of the choke assy levers. Also, could you present a pic of the spring affixed to the manifold. A hose is in the way in above pic.

[madisonguy]

Forgive my ignorance... What's the AC spacer? I'll retake the photos after work today.

Thanks,
John

[thecatseye66]

The AC spacer is the Air Cleaner spacer...it is the big round thing on the top of the carb that the air cleaner sits on. You may have to remove the hose with the EGR valve that should be connected to it or you might lift it off as one solid unit.

[madisonguy]

I'll take some more pics tonight.

[A.P.]

I'll give it a shot on to what I see wrong. It seems that its missing the spring on the vacuum choke. The spring usually closes the choke butterfly plate when you pump on the gas before turning on the engine, here is a pic of my choke on my q-jet carb.

[madisonguy]

Here are some better pics... Thoughts, anyone?

[rage'nrat638]

the last picture is the spring coil box ....which moves from the heat or cold from the intake manifold.....that when cold close's the carb choke plate..


thats where your problem is.........

when cold....spring should be all coiled up (smallest)
and pull the chock closed....


as the intake heats up....the coil gets bigger....and pushed the rod up
to open the choke completey.....



the rod length is the main factor
the spring on the choke just helps push the choke closed when closed.....

your pal mark

[rage'nrat638]

in this picture the carb linkage is hitting the coil spring box keeping it from closing as well.....

[madisonguy]

Thanks a lot for your help, Mark and others. I'll order a new coil spring and hopefully that will fix the problem -- the current one is in pretty bad shape. With any luck I'll be dispensing advice someday instead of just soliciting it all the time...