weber adjustment question

[jchatfield]

I recently installed watershield air cleaners on my 72 911 and adjusted the Webers as I normally do. The problem is that I now get popping in the carbs (I always have interpreted that as lean) as soon as I touch the throttle from a standing start.

If I richen the mixture it gets better, but I eventually get backfiring out of the muffler (too rich), but some of the popping in the carbs remains! How can this be? Did the popping always occur and I did not hear it with the standard airbox?

BTW, it's a 2.4, 8.0 compression, MSD 6 ignition, solex cams, 145 mains, 60 idles 180 AC. The float levels are correct and the carbs are balanced.

Thanks,

Jim
1972 T

[john walker's workshop]

find out which stack is popping by holding your hand over them. then deal with the one(s) you need to. some dirt in the idle jet, or passage, an adjustment that's one way or the other from perfect, dirty needle, or carboned up needle bore, etc.

[rs911t]

Jim, I've dealt with a lot of this lately. Like John said, look for plugged idle jets. Also, make sure you have all the o-rings on the idle jets and mixture screws.