A minor weirdness with my '71 Dart: the idle's quickly been growing progressively rougher over the last couple of days, and it's been growing easier to flood and much harder to de-flood on cold startup. The car is almost bone stock: a Carter BBS 1bbl carb, a points-and-condenser ignition, etc. Today on the way home from having picked up my other half at the gym, the idle at red lights was rough enough to make me throw it in Neutral against the possibility of a stall. Got home, went to the back of the car — whoah, major rich "chuff" from the exhaust. Flipped open the hood and checked the idle mixture screw on this almost-new carburetor: definitely not loose, properly resistant to turning in either direction. I used my fingers to turn it clockwise, and the idle came up and smoothed out as I leaned the mixture screw most of a full turn or maybe even a little more than that.

The screw definitely didn't loosen on its own in response to engine vibration or anything like that, and the change from a smooth idle to a rough one was pretty quick, over a small amount of driving and a few days. Whuh? Weird! I'll have to keep an eye on this.

The funny(?) part is that I filled the tank the other day, checked the fuel economy, and found I got 20.25mpg (U.S. gallons), ~24.3mpg (Imperial gallons), 11.6 L/100km (rest-of-world measure). Pretty good, considering the whole tank was consumed in very-cold-start short trips!

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

Sounds like the needle valve has something stuck in it, or the float is sinking...........

Quick fix for the needle valve is to pinch off the fuel hose and run engine to it almost dies, the unpinch the hose. Any tiny particle gets flushed out because the needle valve is out of the way....

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Ed
64 Valiant 225 / 904 / 42:1 manual steering / 9" drum brakes

Quite sure there's no problem with the float or the inlet needle and seat. Thanks, tho. I'll keep an eye on the carb and a screwdriver in the glovebox!

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

dan,
you need to smudge that demon out of car ...get some white sage light it wave smoke over ,under and in car LOL

This is your '71 Dart you're talking about? The answer is clear. I'll take it off your hands (for a small fee, of course). Now, I know you're in Ontario and I'm In BC, but the drive out west is quite nice this time of year..... When should I expect you?

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1970 four-door Dart, 225/A-904/2.45 gears. 0-60 in twenty three minutes!

There's a Dart/Demon joke in here somewhere, but I can't quite find it!

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

Yup, this one.
*Chuckle* The problem is, every time I visit the Pacific Northwest, it gets more and more difficult to go back.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

Sorry to get off topic here, but wowzers thats a beautiful Dart!

Far as the BBS goes, I have never owned one that didn't end up with the problem you describe. I refuse to run them anymore. In fact, the one slantsixbob got from you had something odd occur with it as well, the end result being the entire carb flooding to the point of fuel coming out the top of the bowl where the accelerator pump rod goes through.

Still haven't really figured out what went wrong there.

I've had much better luck with the 1920s in most regards (they all have drawbacks), so I choose to run those instead.

My .02

~THOR~

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1984 D100 Shorty Custom
Certified Auto Appraiser - RevItUp Classic Appraisals
President - Cherry City Bombers CC
Part of Tyrde-Browne Racing

One time i filled up Duster with a different brand gas and for several
days the idle was really rough, later filled up with the regular gas
normally use and everything was ok

I know what you mean. I moved here from Winnipeg.......

So where are we on the dart? Should I start a pot of tea?

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1970 four-door Dart, 225/A-904/2.45 gears. 0-60 in twenty three minutes!

Thanks!
Odd. How many have you owned? This is the first time I've run into this with a BBS.
Okeh, send 'em all to me.
That'd be a stuck inlet needle and seat. I always recommend looking carefully at the soft parts (gaskets, inlet needle, accelerator pump plunger cup) and renewing as necessary before installing a new OLD stock carburetor.
And me, quite the other way around; I've never met a 1920 I was quite all the way 100% happy with and prefer the BBSs.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

Dan- it's that chicken. You gotta watch those chickens, they are sneaky.

It's 1:14 in the morning; too late to start out.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

That's ok. Tomorrow's fine. Just let me know when you hit Langley and I'll start the water.

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1970 four-door Dart, 225/A-904/2.45 gears. 0-60 in twenty three minutes!

Thats a really sweet Dart Dan.

Sadly, I have no answers for your problem. I have the same problem with my BBD on my Dart. Every 10 days or so, (its daily driven) one or both mixture screws backs out a bit. The springs on the screws have plenty of tension on them, and provide what should be plenty of resistance. I have been fighting this every since I put the super six setup on last April.

I will be watching this thread to see if anyone has any ideas.


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