My carb'd 88 runs rich at any RPM above idle after the engine is full warm. I've been running through some of the diagnostics from the FSM and have found something I don't understand.

In order to check the feedback system there's a light green wire underneath the glove box. According to the book, when an ohmeter is connected between this wire and ground the meter should "swing" at idle and WOT and should "stay after deflect" at any other position.
What I'm getting is a swing between 3K ohms and 0 ohms at idle (about a second each) with an increase in the ohms (to about 10K) off idle dropping back to 3K and then alternating as it does at idle- then it starts running rich. The micro switches test fine as does the air temp switch, haven't checked the mixture solenoid yet.

What the heck am I looking at? Is what I'm seeing acceptable? I'm thinking that the mixture solenoid may be at fault- sound resonable?

On the carbureted Zuk you should be able to check out the feedback carb. system with just the check engine light circuit. Did I miss something in your problem description?

You're right. You just flip the switch under the steering column, run the engine till it's warm and then hold it around 2000 rpm- if all is well the light flashes (mine dosen't). But that just checks the entire system. The next step is to check individual components - micro switches, mixture solenoid, O2 sensor-and finally the ECU itself. So far it looks like the solenoid may be bad, but I haven't tested the ECU yet.
It's really a pretty simple system, I was just tired last night and wasn't thinking very well.

I have a couple of ECU's if your need one.
Doesn't sound like an ECU though, everyone I have seen go bad just quits all together.

It's the mixture solenoid- dead as a dooorknob. .... I just wonder if it can be rebuilt as I really don't expect to find anything but the whole carb.
Hey, you wouldn't have any spare EFI setups (Or decent lift springs, header .... whatever Suzuki parts I can get) you'd like to trade for some Yota axles (t-case,tranny, motor etc..) would you?
I lost my job and will have to go low low buck on my zuki, so that will mean dialing in the 1.3, stock axles w/springover and 31's. (starting back to school in January-so I'll be broke for a while!), ;)

I don't have anything but stock suzuki parts.
I don't particularly need anything at this time, already have toy axles, spool, lock right.
I just need the motivation to get working on it.