Last summer my car was having fuel problems, 78 L-82. I would drive it into town (2mi) and go get my beer. After returning to the car (5min) the car was flooded with fuel. Took a lot of grinding with my foot to the floor and it would start with a cloud of black smoke.
Had the Q-jet (53k) rebuilt and problem solved. Ran great all winter and now that it has gotten hotter the same problem is back. Gotta keep my battery fully charged to enjoy this old beast.
I once read that a lot of problems blamed on these old Q-jets are not where the problem lies.

Any ideas will be greatly appreciated.

 

Dayum old cars.....


Got mine up and running and even with a mini starter it doesn't have that "let's go now" thing going on. Still acts like it's not gonna turn over like it does when cold.


And then the master cylinder fails! Thank god I was in the driveway....


No help, but I didn't want you to feel all alone...

 

Just a guess but what kind of fuel filter you running? To me it sounds like the float may be sticking. If some dirt gets in the needle and seat it will stick the float open. Suggest to check for dirt in the tanks and make sure you have a fresh clean filter!

 

It could be that the choke is still closed but the engine is warm enough that it needs to be open. Next time you need beer, before you try to start it, pop the hood and take off the air cleaner cover to see if the choke is still closed.

 

First thing I would check

 

something similar happened to me every summer... spent a lot of time and $$$$$ trying to figure it out..

it was that the fuel was vapor locking and this is what prevented it from working... had a lot of problems with my holly at the time, the front bowls were hot and as said, vapor locked the whole system.... i would bet this is your problem,,, get a 1/8" fiber spacer between your carb intake manifold, also have a good fuel return line... this will probably fix your problem...good luck...

 

Find out first if you have too much fuel or not enough, although the cloud of black smoke suggests too much.

Ensure that the choke plate is fully open during hot re-starts. Don't pump the gas prior to cranking the engine. If it's still flooded, this suggests that the float level is too high or the valve and seat are leaking as others have suggested.

This presumes that you have the correct three port fuel pump arrangement and not some aftermarket downgrade.

 

Thanks everyone for replying to this thread.

Pauldana...The carb spacer is in place.

Ktkelly...I had the same experience with my starter then I read here on this forum that the ground wire is a main culpret with slow turn-over. I removed the wire from the frame, shined everything up and re-installed it with dielectric compound. Presto...no more lazy starter.

Mike & 76Ray....Sitting in my garage, I couldn't get the car to duplicate the problem of sudden flooding I did notice the plate was sitting about 1/3 open at operating temp. Got that adjusted so well see on the next trip to town. If it's not cured I'll start at the carb filter and work my way back to the tank stopping by the pump and check for three ports. I didn't have any time today to mess with it but i'll get to it tomorrow.

Thanks again for your time....Alex

 

[QUOTE=Mike Ward;1574411871]Find out first if you have too much fuel or not enough, although the cloud of black smoke suggests too much.
Ensure that the choke plate is fully open during hot re-starts. Don't pump the gas prior to cranking the engine. QUOTE]

IF YOU ARE IN THAT MAJIC AREA where the choke is partly closed even though the engine is hot, holding the gas peddal to the floor should "unload'' the the choke plate (to fully open ) so it doesn't pull too rich. Many people don't understand the unloader function or have it set correctly.

 

I like to adjust the choke kinda 'loose'.
By that, I mean with a cold motor, depress the gas to set, or close, the choke plate.

Mark the choke spring thermostat housing on the side of the carb, a piece of tape at 12 o'clock will do, then loosen the 3 screws in the housing and turn it til the choke plate starts to open. Then turn it back and go just a little past closed. See how much you changed it by looking at the tape. Check that the choke plate operates correctly, it may need to go back beyone closed still a bit more.

I figure I never drive my Vettes in real cold temps so I don't need the long warm up. If you do drive in the cold, do this when the outside temp is the coldest you'll actually drive in.

I also like to lower the fast idle. Maybe 1200 rpm.

 

If the car sits for any extended period of time make sure you use Fuel Stabilizer. Keeps the carb from gumming up.

 

Take a different car to the beer store, that's one gamble I wouldn't take

 

Howdy Mike......Errr, I mean L-82.
It's great to report to everyone that I had some success today. Pulled the top plate from the main carb body, removed pull-off and choke and started checking. First checked the cleanliness of the float bowl and seat..metering rods great....everything is clean as can be. Checked the float height with that little plastic ruler that comes with the kits...(just call me the pro..) and everything is clean and looks good...."EXCEPT" the little cam that fits onto the choke shaft and goes through the top body to the butterfly plates via a little linkage was laying in the bottom the the housing. I'm hoping this makes sense because everything seems to be "IN-TUNE" and I'm celebrating.
There is a golf country club about a quarter mile behind my house and the developers have put in paved streets for about 100 homes but not one has been started....(i'm loosing my country solitude) These streets have one way in and one way out and wind around for about 1/3 to 1/2 mile. Just what the doc. ordered to test my new found power.
Much more response, the cough at throttle stab is gone and I thrashed it pretty good around the deserted streets. It drove like I always suspected it could and much as I tried,,,I could not get it to duplicate the sudden flooding problem. The primary plates are wide open an op. temp and it drives great.
I believe I have been running around in this "thang"since last fall with the primary plates almost closed. There is no way that little cam could come off the choke shaft by its self. It had to be that way from the so-called Q-jet expert that resides locally.
I wish to thank everybody who answered this thread and .....just got me off dead center and ready to do battle with the Q-jet. Sometimes it seems to me that this old Vette likes to sit in it's air conditioned shop with the hood up. I think it just loves that position like an old dog laying on the front porch.
I just might drive it in the 4th of July parade for my birthday.....I'll be 68.......that is if its not too hot...(it doesn't Like hot days) and neither do I ............

 

Hey Rich, pretty much how things are in my neck of the woods!
Kinda why I've been playing with my cars rather than working for the last year.......

 

Yep...It's a fact. There's not many mechanics around that know anything about these old cars so ya gotta get under them and do it yourself......looking forward to my lift. That's gonna be some fun even though my wife thinks i'm nuts