Weber tuning - mixture screw has no effect

[Christien]

Tuning the Webers this weekend I found no change from turning #5 and #6 mixture screws all the way in to all the way out. I pulled the jets to see if they were clogged, but they weren't. I sprayed them with compressed air anyway, but still got no response from the changing the mixture screw.

I did notice there's no rubber sealing ring on the jets, though there isn't one on #4 either, and the mixture screw for #4 is working just fine.

I bought these carbs maybe 5 years ago, freshly rebuilt. They worked as a plug and play on the old engine, but when I swapped in the 3.0L I rejetted them and retuned. I've never managed to get the tuning right, despite several attempts. I didn't check the float levels this weekend, but I have on a previous tuning attempt and the levels were good (or adjusted to be good, can't remember, it was last summer).

I'm getting a bit of popping out the top of the carbs and some small pops on deceleration, but only between 2500-3000 rpm (if I'm at 5000 and let off the gas it's fine). Idle is very steady at about 800, 850 rpm.

Where should I start with trying to diagnose what's wrong? Bad jets? A clog inside somewhere? Vacuum leak?

[1QuickS]

Review the article: "Clearing "Hidden" Fuel Gallery"

On this web page: Performance Oriented

[Christien]

Just had a quick look - can that be done with the carburetor in place or do I need to remove it?

[carrerarsr65]

i just performed the cleaning hidden gallery ,take the carb off to do it right and reset float the car now runs like a beast,should have done it in the beginning of summer good luck, and paul is da man

[1QuickS]

It can be performed in the car, tops of carb bodies require removal. If a gallery is blocked then you will need to remove carb from engine to remove the lead plugs to gain access to the "Hidden Gallery". The previously referenced web page has the lead plug removal/replacement procedure provided just preceding the "Clearing Hidden Fuel Gallery" procedure.

[Christien]

OK, just wanted to know if need to order gaskets first. I'll leave it till the winter, order some gaskets and remove the whole carb and do it right. Thanks!