Rich idle

[73ss]

Have a 17084228 single main airbleed with the following specs:
Upper idle .070
Lower idle .070
Idle down  .052
Main air .086
idle tube  .037
idle port .085
73 jet 50m rod 5/16 float setting,  .110 idle bypass. All sizes are stock except the idle tubes, idle ports, & bypass.

454 chev 228/238 114lsa  .540 lift 10:1 compression.

Carb has a rich stinky idle.  Gas analyzer verified with 2000+ ppm HC @ 850rpm idle. 9:1 A/F ratio.
There is no nozzle drip.
Mixture screws about 4 1/2 turns out. They are the fine thread type. If I turn them in idle becomes un-stable.
I re-torqued the intake, checked for vacuum leaks etc.
Timing is 16 degrees.
Carb runs excellent otherwise, Crisp response, no bog, starts right up, Kinda hate to mess with it but I'm worried about cylinder washdown with that rich of an idle. It stinks up the house as well.
I'm thinking maybe I went too big on the idle tubes?
How many times can a base gasket be re-used? Maybe mine is leaking somewhere and I can't find it? needle & seat?
Anyone have any ideas?

The parts are Cliff's. I had cliff's re-color the entire thing a few years back and it still looks like new.

[Cliff Ruggles]

If you can turn the mixture screws in and slow down the engine then it's going lean, not rich.

The specs you have for idle fuel are actually pretty conservative for one of those carburetors and that much camshaft....Cliff

[73ss]

Thanks for the reply Cliff. I'm suspecting I have a vacuum leak that I'm missing and I have to turn the screws out farther than they need to be to overcome the vacuum leak to get a decent idle? The intake gaskets are fresh this spring.

Maybe It's time to re-gasket the carb as I've had the top off a few times. Are base gaskets a one time use? I've had the carb off several times. I can't detect any leaks by sparying carb cleaner around the gaskets.

Is there anything you would change on the specs?

[77cruiser]

I'd try opening the down channel to .055-57.

[73ss]

I've got it straightened out. Ended up being the needle/seat assy loosened up a tad bit. Or I didn't get it tight enough the first time. Must have been leaking just enough fuel pass the seat threads to screw things up. Re-gasketed everything. all is well. Also had a small vacuum leak in the AC vent system. The fact that I couldn't shut the heat all the way off should have been my first sign..........