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70 Charger 318, BBD 2bbl - idle adjust?

Triplegreen500

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So...I was going to post here asking about setting the hot idle on my '70 318/auto/factory a/c car. I bought it in December, still getting acquainted with it, and all the...."features" from the previous owner.

Like wire nuts in the wiring harness underhood.

Basically what happens when I drive it more than around the block, it starts to hesitate/stutter at cruise, when on the idle circuit. Toe into the throttle, and open the secondaries, and it runs great. Get off the highway, stop at a light...and it stalls, unless I two-foot the pedals. No hot idle.

Well...I just deleted the post I was writing about setting the idle. I was looking through my FSM, found the recommendation to turn both screws in to seat, and out 1.5 turns, and went to do it.

Driver side screw was SIX turns out.

Passenger side screw (the one that's hard to see)....was on the seat, all the way in.

:mad:

Set them per the book, and it already idles better (drove it to work, did this while the engine was still warm...not "hot", but not room temperature, either). We'll see how it does on the drive home. I'm hopeful, though - that would be three for three the last couple days. 1) I ran a new wire for my temp gauge, from the sender in the block to the firewall, to replace a broken OEM wire (I need to get a new engine harness at some point, to get rid of the rest of the freakin' wire nuts...); 2) I adjusted the kickdown linkage and now the transmission actually kicks down when I boot it; and now 3) the carb settings.

She's gettin' there!
 
Sounds like you are on the right track.
 
Still in the honeymoon phase...but should be sorted out in time for Carlisle! Helps to start with an excellent quality survivor, I'm very lucky! :thumbsup:
 
Your Factory service manual will really come in handy. Who better to teach you how other than the people that designed and built the car. LOL
 
Oh, I know.

I have a locker FULL of manuals at home for all my ICE units - cars, motorcycles, yard maintenance, you name it. The Charger is the only one that I don't have a paper copy for...yet. The .pdf seems to be serving just fine so far though.
 
This was not so much a "discover the manual" experience, but part of the "I'm finally driving it enough to start noticing and sorting these things out" experience.

Today's commute to work - 33 miles - is the furthest single trip I've made in it to date.

Honeymoon phase, like I said :)
 
So...I was going to post here asking about setting the hot idle on my '70 318/auto/factory a/c car. I bought it in December, still getting acquainted with it, and all the...."features" from the previous owner.

Like wire nuts in the wiring harness underhood.

Basically what happens when I drive it more than around the block, it starts to hesitate/stutter at cruise, when on the idle circuit. Toe into the throttle, and open the secondaries, and it runs great. Get off the highway, stop at a light...and it stalls, unless I two-foot the pedals. No hot idle.

Well...I just deleted the post I was writing about setting the idle. I was looking through my FSM, found the recommendation to turn both screws in to seat, and out 1.5 turns, and went to do it.

Driver side screw was SIX turns out.

Passenger side screw (the one that's hard to see)....was on the seat, all the way in.

:mad:

Set them per the book, and it already idles better (drove it to work, did this while the engine was still warm...not "hot", but not room temperature, either). We'll see how it does on the drive home. I'm hopeful, though - that would be three for three the last couple days. 1) I ran a new wire for my temp gauge, from the sender in the block to the firewall, to replace a broken OEM wire (I need to get a new engine harness at some point, to get rid of the rest of the freakin' wire nuts...); 2) I adjusted the kickdown linkage and now the transmission actually kicks down when I boot it; and now 3) the carb settings.

She's gettin' there!

A curiosity question....
You mention a Carter BBD carb, but go on to mention about "toe in the throttle and open the secondaries". A Carter BBD for a '70s vintage 318 engine is a 1-1/4" 2 Bbl carb. The dimension refers to the front to back dimension of the flange mounting holes. It is a 1-7/16" throttle bore carb. UNLESS SOMEONE swapped it out for sonething else.....could be Holley after market 2 bbl replacement (not a model 2300 series 4160). The ORIGIONAL Carter BBD woild be jetted lean for emissions and have (likely) idle mixture screws with limited adjustability; some models even had the mixture screws staked to prevent them from being turned out too far. If your carb had this feature and the mixture screws were forceably turned out too far, the result was the mixture needle broke off in the carb body.
Has your original problem been fixed? Please advise....
BOB RENTON
 
I likely misspoke about the secondaries. Wrong term. Once I get out of the idle circuit, it was running great. The idle circuit - with one screw six turns out and one screw bottomed on the seat - seems to have been the issue. Both screws 1.5 turns out from the seat, makes it much happier!

Driving home after the adjustment, it ran a thousand times better. I still have a slight low-throttle stutter, but I think I traced that to a nut that came off the + terminal of the ignition coil! The lead was still there - the ring terminal snagged on the threads of the terminal - but I could see it making intermittent contact and causing the stutter. Threads are stripped on the terminal, so a new coil is on the list for next weekend. Once I do that, if the stutter is still there, I may start opening those mix screws a quarter turn at a time. But I suspect actually bolting the wires to the coil properly will help - a lot!

This is all (gradually) coming back to me! It's been decades since I did much with a carbureted car. All my other toy cars are EFI 2.2 and 2.5 Mopar turbos, and the other carburetors in the garage are attached to motorcycles and are completely different animals! The theories are all still rattling around upstairs...just have to get used to the geography again is all. :D
 
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