Idling rough and smoke... help

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Brian Bearor

Brian Bearor

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Need some help.

63 Valiant. Just bought the car. Has 62k miles but has been sitting. Engine is now idling rough. Black smoke when starting them blue smoke when running. Better when warmed up but, still smokes a bit.

Replaced the plugs, wires, distributor cap recently and was running great. Didn't do the points even when smoking. Smoking isn't new.

It does have an exhaust leak. Not new.

Pic is of the spot after starting. Link is a video of the engine running.



Recommendations for fixes?

Thank you

IMG_20210514_195254008.jpg
 
Black smoke is running rich. How is that carb? Choke work? How is the mixture ajustment...reve it , see if puffs of black smoke come out exhaust that means sunburnt fuel or running rich
 
Brian Bearor said:
Choke is working. What do I look for... mixture adjustment? Novice and know just enough to o get me in trouble. Recently rebuilt.
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IF it's a two barrel, look for mixture screws near base. A basic from scratch setting is turn them in till they stop, then back out about two turns. Start engine and tweak in till idle stumbles in each direction clockwise and counter clockwise. Sweet spot is in between and at best idle. You can get more detailed with a vacuum gauge, what I told you was a basic on the fly ajustment.
 
Running ok then all of the sudden running rough and smoking points to one of two things for me;
1. Stuck choke
2. Crap in the needle and seat overflowing the fuel bowls.

In that order. Pull the air cleaner off, start the engine. Look down the carb and see if you see fuel dribbling while it’s idling. That’s a dead giveaway
 
TT5.9mag said:
Running ok then all of the sudden running rough and smoking points to one of two things for me;
1. Stuck choke
2. Crap in the needle and seat overflowing the fuel bowls.

In that order. Pull the air cleaner off, start the engine. Look down the carb and see if you see fuel dribbling while it’s idling. That’s a dead giveaway
Click to expand...
I agree I was thinking "it's dumping fuel" but didn't want to use that terminolgy...
 
Dartswinger70 said:
IF it's a two barrel, look for mixture screws near base. A basic from scratch setting is turn them in till they stop, then back out about two turns. Start engine and tweak in till idle stumbles in each direction clockwise and counter clockwise. Sweet spot is in between and at best idle. You can get more detailed with a vacuum gauge, what I told you was a basic on the fly ajustment.
Click to expand...
It is a single barrel. Use the same procedure?
 
I think he said it was rebuilt, maybe not setup? Also keep in mind on these older cars timing should be checked along with tweaking the carb.
 
Another thing to check is if the distributor has come loose. If you can twist it by hand it’s too loose.
 
Dartswinger70 said:
I think he said it was rebuilt, maybe not setup? Also keep in mind on these older cars timing should be checked along with tweaking the carb.
Click to expand...
He said nothing of the carb being rebuilt. I think you’re giving great advise but maybe jumping forward a little. A little diagnosis will go a long way toward not leading him down a rabbit hole.
 
TT5.9mag said:
He said nothing of the carb being rebuilt. I think you’re giving great advise but maybe jumping forward a little. A little diagnosis will go a long way toward not leading him down a rabbit hole.
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Thanks but it was recently rebuilt.
 
What did ya find out?
And yes he mentioned the rebuild early on. It's a reading comprehension thing I get it.,,
 
How long did it sit? Your fuel might be bad. Had the same issue a while back, dumped the tank. filled with fresh gas, got it to stop smoking. Also sounds like it's running rich
 
Dartswinger70 said:
IF it's a two barrel, look for mixture screws near base. A basic from scratch setting is turn them in till they stop, then back out about two turns. Start engine and tweak in till idle stumbles in each direction clockwise and counter clockwise. Sweet spot is in between and at best idle. You can get more detailed with a vacuum gauge, what I told you was a basic on the fly ajustment.
Click to expand...
Final had a break to try it. Seems to have done the trick. Still smoking a bit but not as bad.

May try draining the tank and putting a new fuel filter. Some suggested that. It has sat for a while. Do you think it may help with the smoking?
 
Remove the air cleaner. GRAB the carburetor with both hands and twist it back and forth like you are trying to twist it off the manifold. Pay CLOSE attention to see if there's any play back and forth. They have a bad habit of the screws working loose, especially right after a rebuild because after a heat cycle or two the screws need retorquing back down. That will make one run rich, lean and like crap in general. Also as mentioned, make sure the choke is opening completely open when it's warmed up. The choke plate should be vertical when the engine is up to temperature.
 
RustyRatRod said:
Remove the air cleaner. GRAB the carburetor with both hands and twist it back and forth like you are trying to twist it off the manifold. Pay CLOSE attention to see if there's any play back and forth. They have a bad habit of the screws working loose, especially right after a rebuild because after a heat cycle or two the screws need retorquing back down. That will make one run rich, lean and like crap in general. Also as mentioned, make sure the choke is opening completely open when it's warmed up. The choke plate should be vertical when the engine is up to temperature.
Click to expand...
Will try that thanks. Choke is working properly.
 
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