Running Rich vs Lean

[Guest ZombyWoof]

I've never messed around with this, but what factors depend on where you'd want this set?

Type of climate? Type of driving? Typle of fuel?

Or just whatever "runs" right?

[Jim Cannon]

The mixture screws only adjust idle mixture, not driving mixture. So adjust them for a smooth idle, whatever works.

To adjust running mixture you change out the metering rods and the main jets.

[Guest pfloro]

<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">I've never messed around with this, but what factors depend on where you'd want this set?

Type of climate? Type of driving? Typle of fuel?

Or just whatever "runs" right?</div></div>

I'm not an expert by any means but these are some things I've read & experienced over the years:

In terms of proper combustion, the engine needs to have just enough oxygen to 'burn' all fuel mixed with it. Hey..., it's a chemical reaction which produces heat and expands the air in the cylinder... Too little 02 and you are running rich, too much O2 and you're running lean. A properly setup carb for a given engine should handle all driving conditions without a problem. I understand that today's ethanol blends (ie: E10) might requires a little tweaking on older cars (pre-WWII). If you live at a high altitude (> 10,000' ?), the carb needs to be set-up to compensate for the less dense air.

Hope this info helps.

Paul