Idle Mixture screw, should it be blunt?

[JC6715]

Just finished rebuilding the carb on my 2 barrell 289 with the Autolite 2100, when I pulled the idle mix needles one of them is very pointy and the other is rather blunt. I'm guessing this isn't right and they should both be pointed. Where would I find a new one, and could this be the cause of the stumble I get right off of idle when accelerating? Thanks a lot guys.

 

[D.Hearne]

Should be sharp not blunt. Just get a replacement from another carb. If you cant find a replacement, send me your address at [email protected] and I'll send you a couple, I've got a half dozen 2100's sitting here.

 

[JC6715]

Thank you thank you, I've been looking for a replacement, but haven't found one. I'll look a little more, but if I can't find one, I'll shoot you an email. Thanks a lot I really appreciate it.

 

[thehueypilot]

Just finished rebuilding the carb on my 2 barrell 289 with the Autolite 2100, when I pulled the idle mix needles one of them is very pointy and the other is rather blunt. I'm guessing this isn't right and they should both be pointed. Where would I find a new one, and could this be the cause of the stumble I get right off of idle when accelerating? Thanks a lot guys.

Idle mixture screws have nothing to do with an off idle stumble. It's more likely your accelerator pump shot size and ramp.

 

[JC6715]

Idle mixture screws have nothing to do with an off idle stumble. It's more likely your accelerator pump shot size and ramp.

Pardon my ignorance, but what does that mean? How would i check that? Thanks for helping out this noob.

 

[thehueypilot]

You can make an adjustment to your nozzle size(go bigger or smaller diameter). Which is the part of the carb that you see the gas shoot out of when you quickly open the throttle. The duration and amount is controlled by the plastic colored cam attached to the throttle shaft. If your car backfires/falls on its nose during launch you may be running lean in the accel circuit so you would want to move up to the next size nozzle. (example....#26 move to #28)

 

[JC6715]

Right on, thanks

 

[D.Hearne]

And where's he going to get these different cams and squirters? He's got an Autolite 2100, not a Holley.

 

[thehueypilot]

And where's he going to get these different cams and squirters? He's got an Autolite 2100, not a Holley.

Duuuhh.....your right I guess I should read more carefully. I think you can get some parts from "Pony Carbs." http://www.ponycarburetors.com/

This is what they said.......

"This is the finest two-barrel carburetor that has yet to be made, it is simply state-of-the-art today. Unless dirt gets in it, it will basically just keep running indefinitely. Nobody has ever built a two-barrel carburetor as good as this one is. One calibration 1968 289 (C8ZF-G) does have several engineering problems which we do correct (hesitation, flat spots and surging on acceleration)."

 

[10secgoal]

Idle mixture screws have nothing to do with an off idle stumble. It's more likely your accelerator pump shot size and ramp.

 

[D.Hearne]

Duuuhh.....your right I guess I should read more carefully. I think you can get some parts from "Pony Carbs." http://www.ponycarburetors.com/

This is what they said.......

"This is the finest two-barrel carburetor that has yet to be made, it is simply state-of-the-art today. Unless dirt gets in it, it will basically just keep running indefinitely. Nobody has ever built a two-barrel carburetor as good as this one is. One calibration 1968 289 (C8ZF-G) does have several engineering problems which we do correct (hesitation, flat spots and surging on acceleration)."

Same can be said about a Holley.