sanjosebass

So this weekend I was able to tune up my 1966 Ford 289 by doing the following:

1. New Dizz Cap & Rotor
2. New spark plug wires
3. New plugs
4. Converted to a Pertronix electronic ignition
5. Adjusted the Edelbrock #1404 Carb
6. Timed her

And guess what, she is running like champ! I was watching the Edelbrock videos and figured out that the guy before me had some of the carb hoses in the wrong spot. The timing vacuum hose was where the manifold hose should go. Also, while I was watching the video they show how you can adjust your carb for Rich or Lean performance.

Mind you, the guy on the Edelbrock video stated that the two front idle screws only manage idle, and not general performace. So here is the million dollar question:

What are the advantages/disadvantages of running a rich or lean idle setup?

He also mentioned that for performance engines running a rich configuration may be better.....

Anyhow, I am new to all of this so maybe you guys can shed some light.

Thanks!

67mustang302

You want lean best idle. More fuel could = flooding or at the very least it's extra fuel that washes oil off the cylinder wall(the microthin film left after the rings scrape it) and cause excessive wear. Some performance apps need to run a tad rich because of fluxuating/weak idle vacuum, to make sure that the idle circuit delivers enough fuel to keep the engine from idling rough/dying as the idle circuit becomes lean when the vacuum fluxuates. Either way, you want the idle to be as lean as you can get it while still having the best idle(whatever that may be fore the application. Hence the term "lean best idle."

Starfury

For performance, a slightly rich mixture will give you a hair more power, but you shouldn't worry about that. It's really hard to adjust a carb that precise, especially an Edelbrock. Great carbs for street cars (I love mine), but not as adjustable as Holleys.

kalli

problem is that you cannot really measure the air/fuel ratio without using measuring equipment.
I guess you don't have such stuff, so I'd go by what the manual or their video says to do, or the following which works mostly ok:

turn one screw slowly into lean direction until you measure/hear/see the idle going rough or lower
turn half turn in direction rich.
Repeat the same with the other screw.

Start over to crosscheck (maybe screw1 has affect on screw2)

kalli

sanjosebass

As always, you guys are awesome.

Thanks! Time to remove the wiring and wrap the engine so I can start the wet sanding process.