308 Carburetor popping issue

90% of carb issues are ignition related. Mike

 

Peter please let us know if your caps and rotors fit correctly.

 

I think our cap electrodes are rebuildable??

As for the sampling tubes they are a part of the tool kit, the front ones were/are fixed on USA cars, but that's where you will find the sampling exhaust risers.
I had a set at one time.....maybe still do

 

FWIW my car pops a good bit, sometimes, on deceleration.

It's really the plug not lighting the moisture off, and as others have said, it comes from uncontrolled ignition well down the headers and muffler.
You can blow them up... just ask me!

So there's a line as to what's "allowed"...

 

Amen, de' carb, it jus' flow, brah…….

 

Damn, impressed with the carb cleaner...….!!!

If a lead plug is not leaking, it is still good....

They test at the tailpipe here now for emissions, so if it passes that, it's good.

 

This guy...amazing.....thanks turbo-joe!

And all of the old school guys helping out.
Great thread!

 

Very nice on the gas analyzer. Soon it'll be fixed and you'll forget you had the problem. My passage problem wasn't cured by carb soaking in Berryman Chem-tool Carb Cleaner and blowing out passages w compressed air. My carbs looked brilliantly clean. I had one cylinder that would not respond. I did a compression test, but felt the motor was wayyy to strong and smooth at rev's to be down a cylinder, but had to know since I was getting quite bugged.

I cannot lie - I conferred with someone who's biz is Weber carb's

http://www.performanceoriented.com/

I spoke with Paul about popping from one cylinder, and the idle mixture screw being unresponsive without large jet size increase. I finally decided to ship him the carb. He thought initially, all-good. He too pushed air thru passages to confirm patency and was satisfied as was I. We scratched our heads, and finally Paul mentioned to pull out a few lead plugs. He called me back apologetic as no problems found. I was considering just buying another carb to be done with it! He mentioned pulling more lead plugs to further the hunt and call me back. He called to say he removed and cleaned 2 or 3 more passages and all was clean, so he persevered and continued to remove more plugs and he discovered under one which seemed to control an insignificant passage was heavily laden with soot and took a bit of effort to clean. He re-fitted new plugs and shipped me back the carb, and without further drama, I set the synch and cyl-by-cyl mixture in quick order achieving a sweetly tuned motor. I'm not saying this is your problem. Kind of a pain, and hope it isn't. But I am saying the gas sample of individual cylinders was the best way I would know of to find the problem.

Hopefully in your case, you snap on new electrical bits, take your car for a great drive and forget the thread. How we love them so!!

 

only for the radio, which is sacreligious to use in a carbed car

 

I don’t think so. I’m not great with electronics. But was does pertronix recommendation

 

Not sure what ohm wires they recommend

 

Good that u checked. Lol

 

How were the caps and rotors btw

 

Fingers crossed that electrics wins the battle. I have 2 MSD-6A units well hidden in the car. I needed this to help CA SMOG (It helped, but wasn't enough). I use resistor plugs with the stock spiral wound CAVIS wires and resistor plug extenders. Revs very smooth with these! The RF emission is crazy bad. I figure I can listen to the radio when the motor is off

 

I meant did the new caps and rotors fit properly. I just got some that have issued

 

Adding to the comments, unlikely to be fuel pressure related as this would affect all carbs and not manifest itself at idle when fuel demand is low.
From past experience -
Compression (and if its low on one bank compared to the other side , probably a cam belt has skipped one tooth ). Been there, done that.
Float levels need to be correct
Valve clearances need to be correct
Ignition timing, & dwell
Rotor cap in servicable condition.
Spark plugs - I've found hotter plugs work best in my car ( NGK BP 6ES )
Spark plug leads - easy to test with a meter or swap to see if problem moves
Air leak at carby base or through throttle shaft bearings (one can rebuild the carbs with sealed bearings).
Ultrasonic cleaning works great, I dissasemble the carb and use water & simple green for 10 minutes or so.