• Got the Contributing Memberships stuff finally worked out and made up a thread as a sort of "How-To" to help people figure out how to participate. So if you need help figuring it out, here's the thread you need to take a look at -> http://www.corvetteflorida.com/forums/showthread.php?t=3581 Thank you, everyone! Rich Z.

tri carb idle adjustment

kip younger

New member
I have a tri carb set up on a 350 sbc, bored 60 over; I'm having a little trouble getting the idle right; the first and third carbs have no idle mixture adjustment screws, only the center carb does, is the problem? Does the 1st and 3rd carb need idle mixture setting screws also? I hope not... thanks - kip
 
Sorry, I guess the link didn't transfer. I copied the info on carb set ups from a web page at a site called "Carbs Unlimited". The center carb is adjusted for idle, the front and rear carbs are "secondarys" that work much like the rear venturi's on a Quadrajet. If you go to the site it also has a troubleshooting matrix that may be of use. Hope this is helpful. This is the web address- www.carburetion.com/tripower.htm

Conventional Idle Mixture Screws that provide a leaner A/F when turned clockwise and richer A/F when turned counter clockwise. The idle air flow is controlled by a conventional screw that opens the Primary Throttles. The following procedure should be used to set the idle mixture and speeds.

1. Fully warm engine and ensure choke is fully open.

2. Air cleaner in place.

3. Set desired speed with the air screw.

4. Adjust the Idle Mixture Screws on ONE side to get the maximum possible RPM. Do not go rich beyond the maximum speed point.

5. If the above changed the idle speed more than 40 RPM, then readjust the speed.

6. Adjust the side OPPOSITE of that in Step 4 to get maximum RPM.

7. Reset the speed.

8. Carefully trim each Idle Mixture Screws to again get the maximum idle RPM.

9. Go leaner just enough to get a 20 RPM drop in speed.

10. Reset the speed to the desired RPM.

11. This is a Lean-Best Idle Set. Setting richer than this will not improve idle quality or performance, but could tend to foul plugs.
 
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