Thoughts on Slant 6/225 Misfire

[Charco68]

Hi folks, I dusted the pollen off my '74 Dart, and made a little interstate trip to see if I could "blow out the carbon," as my late dad used to say. Accelerates and shifts smoothly, kicks down nicely, but come to a light? Idles so sh*tty. Best to put it in neutral, otherwise it burbles, shakes and hiccups. I've included a video of the tailpipe, and engine at idle (the louder humming is the power steering pump I believe, even though the fluid is proper level.) It's had a modest tune-up with new spark plugs, ballast resistor, a timing and carb adjustment (has a Holley 1945.) Thank you in advance.

 

[AJ/FormS]

Compression test?

 

[Bewy]

What did you adjust on the carb? I would look there....

 

[volaredon]

Ballast did nothing for you. Id start with the rest of cap rotor and wires instead.

 

[Murray]

Carb or vacuum leak.

 

[bcschief]

Do a valve adjustment .010 intakes and .020 for the exhaust.

 

[slantsixdan]

Tune-up parts and technique suggestions in this post. Carburetor operation and repair manuals and links to training movies and carb repair/modification threads are posted here for free download.

As a starting point, I'd clean out the carb's air bleeds and its idle circuit as described here.

 

[Charco68]

Tune-up parts and technique suggestions in this post. Carburetor operation and repair manuals and links to training movies and carb repair/modification threads are posted here for free download.

As a starting point, I'd clean out the carb's air bleeds and its idle circuit as described here.

Thank you, Dan!

 

[Charco68]

Hello all; small update. A mechanic friend of mine in FL suggested a can of SeaFoam in my next tank, particularly since this car had been sitting for a while. Filled up from 1/4 to 3/4 of a tank of premium, and a can of SF. Idle has smoothed out a bit, to my surprise. I know it's not fixed by any means, I still have an appointment Monday with a new mechanic here in Richmond. I'll share this before/after SeaFam, then an 'after-after' post-service. Happy Saturday!