I'm tuning for:
- WOT: 12.2, and hit that spot on.
- Primary Acceleration: 14.0, actually achieve around 15.5 (don't like it, but it does accelerate and run good).
- Cruise: 15.5, actually achieve around 13.9 (don't like it but it does run nice).
If I choose the very next available lean setting, it goes WAY too lean on primary acceleration.
If I choose the very next available rich setting, it goes WAY too rich on cruise.
So, it is optimized. Like I said, disconnect the AFR gauge and let anyone drive it, and they will talk about how great the car drives. A local shop that did the alignment for me, the owner of the shop told me his tech came back and said, "That ole Scamp runs good!"
And it does. I've tried to find a shop that could make custom metering rods that would hit my target AFRs, but have not found one. I have designed my own metering rods based on the accuracy of my spreadsheet in correlation to what the AFR gauge reads.
As far as the AFR readings, I don't pay attention to the AFR gauge until the engine is actually firing. And even as soon as it fires off, it responds to the engine exactly as I expect. Rich when choked. I get a rich spot when I blip the throttle and the pump shot hits. It was lean when cranking only when I had the 750 carb and I wouldn't pump the throttle or use the choke because I thought I was flooding it. It was only showing lean then … and that's when I realized HA, I'm not flooding it at all. I'm starving it. The AFR gauge showed me the error of my way. As soon as I went to choking and pumping, BOOM. Fires right up.
What threw me (what I didn't know), was back before the AFR gauge, I did pump the throttle a time or 2 before cranking, then a couple more times while cranking. But the carb was either empty or somewhat empty, so the pumping was actually pumping nothing (that's what I didn't know). But I thought I was pumping raw gas in at each time, and after a few pumps with no start, I though it was flooding … so I would stop pumping and keep cranking. After the AFR, I realized the pumping wasn't effective at first, until the carb filled. I now pump it continuously (if it hasn't started in a few days or more) and keep pumping until it hits a lick. After it hits a lick I slow the pumping down and it fires right off. After it cranks it has to be revved (gently) to have the pump shoot in even more raw gas to keep it running. It's a rhythm. But after 15 seconds of doing this, its ready to idle on its own, choked. This is all based on it not having run in a few days.
I drove it to work today. So when I crank it cold to go to lunch, it will require a bit of choke and just a pump or 2 and it will fire right up. Because the carb has gas in it from driving it this morning, so the couple pumps to crank it at lunch time are fully effective. Once the engine is warm after lunch, I just turn the starter, followed by a push of the pedal about a quarter way down (no choke), and it fires up quickly. The AFR gauge made starts quicker and easier by pointing out what was actually going on versus what I *thought* was going on.
7milesout
