72Tornado

Okay, so I took my 72 out for a drive today, and it was running fine as usual...although since I got the car last Wednesday I would occasionally experience a slight hesitation when hitting the accelerator, but certainly nothing major enough to get worried about. Same thing happened today on my way to get a haircut, but it was hesitating more often, and would stutter randomly when just driving along. On my way back, the hesitation and sputtering started to get a lot worse, to the point where it would be doing it all the time, no matter what RPM I was at. I pulled off to check out the carb and it looked ok - the linkages still looked fine (though this is my first experience with a carb'd car and as such I don't know as much about them as I do an EFI system) and nothing was blocking the throttle plates or anything...so I decided to try to drive home. It was still hesitating and sputtering badly, but once I got on the highway it was fine - for about 15 seconds. It then began to get even worse, I'd hit the gas and the revs would jump a tiny bit and very erratically, until the engine simply died going down the highway at 55. I pulled off, checked it again, no idea what do. I got the car towed and now it's sitting in my garage. The car pretty much refuses to start now, though I did get it going for a few seconds before it just died again. I want to get this thing up and running as soon as possible - do I need a new carb, does this one just need to be rebuilt, or might it be something else entirely? I really want to get it fixed by Monday night (was going to take senior pictures with it Tuesday )...any and all suggestions are greatly appreciated!

BTW, the carb is a Rochester Quadrajet...

comp

are you getting fuel" clogged filter" also check ign.

65LS6C4

Tough to diagnose over the forum... You could have many things wrong, however I would first try a few simple things like changing the fuel filter to make certain that you get decent fuel flow to the carb and verifying that you have spark to the plugs. The hesitation that you experienced all week could be due to a simple adjustment on the carb. If you get it running after changing the fuel filter - you will find a screw that adjusts an arm connected to a metal disk on the side of the carb that holds a diaphram... this provides the engine with a shot of fuel when you step on the throttle... if what you experienced this week was a delay before the car accelerates , try adjusting this arm so that the carb gets a greater shot of fuel.. if it was more of a shudder and a hesitation before the car started try reducing the amount of fuel in the shot.

joe73vette

My first thought was ignition grounding out, points closing or coil wire coming loose. But then I thought of water in the gas - did you just fill up? Joe

72Tornado

Yeah, filled up recently, and my dad put 2 more gallons in it when he came to help me out as I was on the side of the road...

Thanks for the advice guys, I'm gonna see if I can borrow an ignition tester from my friend today, plus I'll check the filter and pump...I kinda get the feeling it might be something a little more major than just a plug wire or something though...

Oh, one more detail to add...when I was on the side of the road, I took off the air cleaner and told my dad to watch the carb to see if anything was obviously wrong when I tried to start it...it started (but was very ready to die and difficult to keep running) but after a couple revs a couple small flames shot from (I think) under the choke...

Daytona69

Similar problem with my old Q-Jet before I replaced it. While driving along, it started hesitating bad and then just died. I tried to re-fire it but had no luck...I was very close to my house so I pushed it home. It turned out to be a stuck float.

72Tornado

Hmm...how would I go about fixing this? Like I said, I don't have very much experience with carbs and very little knowledge on their mainteance:bb...

72Tornado

Ummm....guys?

vttedrm

Try this link. It may help. http://www.corvettefaq.com/c3/quadidle.html

hudman

Do not rule out the water in the gas suggestion. I somehow get water in the fuel regularly from rain (I leave the car outside under a Noah cover). I have replaced everything at the top of the tank (filler, gaskets, rubber boot, etc.) to stop it with no luck.

Anyway, I spent $350 with a mechanic a couple of years ago troubleshooting everything that you are talking about. Turned out to be water. It is easy to check. Just get a siphon and suck from the bottom of the tank (water sinks). Watch your bucket as it fills up as you can clearly see the water at the bottom of the bucket. You can just "vacuum" out the bottom of the tank-you do not have to drain the whole tank. The water will look like an air bubble at the bottom of the bucket. Try it-you may be surprised to see what you find. You symptoms are identical to mine when I had the water issue.

comp

have you check these thing's???? do you have a shop book

72Tornado

Okay, thanks a ton for the suggestions guys, I'll check out the ign, fuel filter, and tank when I get home tomorrow...if that doesn't fix it I need to make the decision between dismantling and rebuilding the carb or just buying a new one...

Oh, and the previous owner gave me the Hayne's repair manual, so I'm good there

rtpilot

If you have a Holly , it sounds like a power valve Failed. Floods the carb. Easy to replace the $8 part. Good luck