Cause of Excessive Smoke after Adding Gas to Tank?

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Coolvibes

Coolvibes

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Last night I added 5 gallons of ethanol-free petrol to the gas tank, because the gauge in the car read about "1/4" tank the previous weekend (I am not sure f that was accurate). Today when I went to start the car, it would not start by turning the key only (that's how I normally start it). After two other attempts, I pressed the gas pedal and the car started, but it was running like it had a bad miss. Coaxed it out the garage, and drove it around the block, but had to sink the clutch and feather the gas to keep it running. Struggled to drive it back home and put it back in the garage, but by now it was smoking from the tail pipe like crazy. Black soot like I have never experienced before, engulfing the garage. Had to turn on some fans and leave the garage door open for 15 minutes to evacuate.....smoke was really bad.

Prior to starting the car, I had checked the oil and it was not above the full mark. I had also touched the second spark plug wire on the driver's side of the engine because it looked like it had a tie wrap around it. I did not pull it off the spark plug. Also, the fuel gauge now read "Full".

So, any suggestions as to what could have caused this smoking / soot producing condition from the tail pipe? The engine is the 273 cu in V8, stock, 2 barrel carb, and prior to this ran flawlessly the previous time I drove it.
 
How much were you driving it before?

Couple of ideas, I'm sure others will post more. You could have gotten bad gas, which is causing the car to run like crap. Just because it's ethanol free doesn't mean it's always good.

If you hadn't been driving the car a ton before, it's also possible that when you added all the new fuel that you stirred up a bunch of crap in the bottom of your gas tank, and fed that crap into your carburetor which is now causing issues.
 
That's why I always bypass gas stations that are getting deliveries. Those trucks dumping fresh fuel into the older tanks, stirs up dirt and moisture that's inevitably in the bottom of the tanks.
I go back later in the day after it settled.
 
My question is do you normally run ethanol free gas? Did you by chance purchase pre mixed fuel at a marina? Was the choke open if it has one? I see you said 2bbl so I’m thinking factory carburetor.
 
i got my electric choke working and put some zinc additive in my oil. gave a friend a ride home and got on it a little and it started missing really bad. i scratched my head a minute and figured out it broke a valve spring on my number one intake valve. thank goodness it was an easy fix. moral of the story is i thought it was something to do with what i had done to it but it was totally unrelated.

the only time one of mine started smoking real bad like what you explained yours was doing, a push rod had wallered a hole all the way through the rocker arm.
 
My guess is you put diesel in it in error.

Give the tank a snif test.

You could drain the tank and add clean new fuel or add some more gas to dilute.
 
Joey4speed said:
Bad gas.
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Asshole A02.jpg
 
krazykuda said:
View attachment 1715676320
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Good morning all, and thanks for your replies. The gas definitely wasn't diesel, as I would have smelled it. The gas station was not being re-supplied when I bought the gas. I have the car only for two weeks, and the previous owner said he used only ethanol free gas, so I put that in also. I hope it's the gas and nothing internal to the engine. The car has been driven only about 3 or 4 times in the last 4 weeks; not very often, and not very far.

Yes, it is the original 2 barrel carb. I will have to check on the choke. I am not too familiar with all the control's yet, but I assumed the car had an automatic choke. If it is a manual choke, I know I did not use (deliberately engage) it between my previous good drive and the latest smoke filled drive.

Now that we are discussing this, I remember the PO said he always put an additive in the gas tank with each full up. I think there are some full bottles in the trunk, so I need to check. Any advice on additives?
 
Well, having the car for only a few weeks and only driven a few times changes things.
Need to create a little history time-line. This problem could be more than a sudden fuel issue.
Flooding carb.
Ignition breakdown...
 
Joey4speed said:
Well, having the car for only a few weeks and only driven a few times changes things.
Need to create a little history time-line. This problem could be more than a sudden fuel issue.
Flooding carb.
Ignition breakdown...
Click to expand...

Agree, I need to develop some familiarity and history with the car. It's like having a new gf and not yet knowing her likes and dislikes; "is it ok to put my hand here?" lol.

I did open a new thread asking about spark plugs and wires as I would like to change those.
 
Im guessing this has occasionally been happening all along, you are just experiencing it for yourself now?
 
Joey4speed said:
Im guessing this has occasionally been happening all along, you are just experiencing it for yourself now?
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If you have points and condenser ignition the condensers will go bad with lack of use and act just like that.
 
Joey4speed said:
Im guessing this has occasionally been happening all along, you are just experiencing it for yourself now?
Click to expand...

Yes, this is the first time for me. The symptoms seem more like a flooding issue, because there was so much smoke / soot. The end of my tail pipe / exhaust points downward toward the ground, and there is now a black circle of soot on my driveway; a lot of unburned hydrocarbon.

I don't think an ignition miss alone would cause that much soot, although I may have been experiencing that as well. Guess I will ask the PO if he ever experienced this.

I appreciate your thoughts and input.
 
Coolvibes said:
Now that we are discussing this, I remember the PO said he always put an additive in the gas tank with each full up. I think there are some full bottles in the trunk, so I need to check. Any advice on additives?
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Is the PO talking about lead additive??? If the exhaust valves have not had hardened seats put in (and a valve job), you may need to put a lead substitute additive in the gas....

Another thought is to check the 'sock/filter' on the end of the gas tank sending unit (gas pick-up tube) that pulls the gas out of the tank... The original ones get old and can 'cave in' and plug the fuel pick-up tube... They make replacement ones...
 
Joey4speed said:
Im guessing this has occasionally been happening all along, you are just experiencing it for yourself now?
Click to expand...


69hemibeep said:
If you have points and condenser ignition the condensers will go bad with lack of use and act just like that.
Click to expand...


@halifaxhops is the guy to go to for distributor parts and/or rebuilding... He restores distributors, can custom curve your spark, and stocks up on old points and condensors, not the new junk at the parts stores today.... If you want a good set of points and/or condensor, talk to him....
 
You have to trouble shoot it first and see what is going on. Black smoke can be a bunch of things.
 
A red flag popped up when you said you never have to pump the gas when starting . My bet it you have a leaking needle and seat .

OR... you filled up at the 2- stroke pump .
 
Gotcha.
Carefully get a look at the carb when its acting up while running.
Not sure of your level of knowledge.
Theres a few things you can do to help clear a flooding carb in the field. But you have to be careful not to cause a fire. Theres many ignition sources around for fuel in the aircleaner and on the intake to ignite. Keep in mind, gasoline vapors are heavier than air and will seek lower areas.
 
I'd be checking on a closed choke first. Explains rough exit from garage, need for high rpm to keep running and black smoke. Then if that turns out to be fine. The dirty float needle happened to me. Gas leaking all around the carb because the float needle wouldn't seat. Engine floods.
 
mbaird said:
A red flag popped up when you said you never have to pump the gas when starting . My bet it you have a leaking needle and seat .

OR... you filled up at the 2- stroke pump .
Click to expand...
Good point.
A bit off subject, but to your point.
I remember when some idiot fuel delivery guy dispensed gasoline into the below ground "Kerosene" marked tanks at a fuel/mini market.
People didn't know they were pumping gasoline into their kerosene cans, then running their space heaters at home.
Needless to say, quite a few fires and an explosion or two later, the investigators figured it out.
Now its very difficult to do that, especially since the tank fill ground caps are color and shape coded.
Point is, the wrong fuel can get into a cars gas tank too.
Okay, back on with Coolvibes issue...
 
Joey4speed said:
Good point.
A bit off subject, but to your point.
I remember when some idiot fuel delivery guy dispensed gasoline into the below ground "Kerosene" marked tanks at a fuel/mini market.
People didn't know they were pumping gasoline into their kerosene cans, then running their space heaters at home.
Needless to say, quite a few fires and an explosion or two later, the investigators figured it out.
Now its very difficult to do that, especially since the tank fill ground caps are color and shape coded.
Point is, the wrong fuel can get into a cars gas tank too.
Okay, back on with Coolvibes issue...
Click to expand...
 
krazykuda said:
Is the PO talking about lead additive??? If the exhaust valves have not had hardened seats put in (and a valve job), you may need to put a lead substitute additive in the gas....

Another thought is to check the 'sock/filter' on the end of the gas tank sending unit (gas pick-up tube) that pulls the gas out of the tank... The original ones get old and can 'cave in' and plug the fuel pick-up tube... They make replacement ones...
Click to expand...
Agree. For a fuel starvation issue. We used to disconnect the fuel inlet at the fuel pump, then blow shop air into the line, more often than not you'd here the bubbling air after you blew the clogged sock off.
It was a quick diagnostic and worked well in those days.
If it ran better, then you would replace the sock.
 
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