I’ve adjusted the 1100 carb quite a bit before, but nothing ever seemed to make all that much difference. Today I decided to do it again—this time using both the oxygen sensor and a vacuum gauge. I was able to lean it out quite a bit. I think I ended up doing 1/2 to a full turn on the idle mix. Dropping the idle speed to about 900 then netted me close to 14-15” in Hg of vacuum (the reading was still a little shaky, but lots better than it used to be) and O2 voltages between about 600 and 800 mV. Going even just a little leaner resulted in the voltage dropping below 475 mV on occasion, and I’m trying to keep it a little on the rich side for now. Unfortunately, after I shut it off, disconnected the vacuum gauge, plugged the vacuum port, and started it back up, the idle had dropped to around 750 rpm and it wouldn’t stay running. So I bumped the idle back up to around 1000, and then it seemed fine.
Result: It’s completely different now—so much smoother. There’s only an occasional shake at idle and the exhaust sounds smoother and better (plus smells better according to my mom lol). The jerkiness that it had if I shifted into 3rd before 30 mph and got off the gas is gone. I actually checked to make sure it was still running at a stop sign too :p. The vibration that I’ve been trying to track down is still there, but otherwise so far it’s a lot nicer.
In addition to the carb adjustment, I messed with my hood hinges. I sprayed all the rivets where it pivots with WD-40. The back of the hood tends to sit up above the fender and cowl unless I push down at the hinge. I loosened the hinge-inner fender bolts, pushed the hood up, and tightened them. Now it sits pretty close. The driver’s side is missing a bolt, so once I get that replaced I expect it to be better. With the WD-40, it opens and closes really easily; with the adjustment, it latches easier. Awesome.