Carb backfire

No I'm not.  It was a soft backfire and I automatically assumed it was from the carbs. And of course I know what happens when people assume.  What else should I look for Troy?

It's a good possibility you have a partially clogged idle jet in one cylinder which will cause a lean, off-throttle backfire.

Or it could just be a very slight exhaust leak in the system somewhere, probably at the head. Look for soot trails on your exhaust, they are pretty easy to spot.

Danny is pretty right on on his diagnosis...I've had that happen, a soft popping or 'chutt, chutt' sound when letting the engine decelerate under load,  a few times over the years on the Cobras 48 IDA's. It never seemed to be noticeable when accelerating...I usually found it was a partially clogged idle jet on one of the cylinders and once it was from a couple of loose header bolts on the headers to head. That was easily identifiable due to the carbon sooting on the white header pipes.

Webers, if that is what you have, can be a bit finicky when the idle jets are not functioning correctly and the air/fuel mixture is thrown off, way moreso than any Holley, Edelebrock, Solex, Rochester, Autolite or Quadra-jet

@ Danny and Hoss

Thanks.  I'll look for soot trails first since I can tighten a bolt.  The carbs are Solex and if the idle mixture is off I'll probably run it over to Scott Sebastian or someone else.  I don't want to go start down a hole i can't get out of.

Robert.  Unclogging an idle jet on a weber is a piece of cake, but I'm not sure where they are on a Solex.  If someone can post a schematic that shows where they are, bring your car by and we'll give it a try.

Great document Gary. Is that the idle jet in figure 17 on page 18 called a "pilot jet?"

Yes, the idle fuel jet is called a pilot jet on Solexes.

I HATE Solexes. But only because people don't maintain them, they get gunked up. They also leak from the throttle shafts. You can have every one of them on every 356 or 912.