More tuning today.
I’ve been having trouble getting the idle below 950 RPM since the initial startup. Turns out I did a bonehead thing by connecting the charcoal canisters carb bowl vent port to manifold vacuum. I didn't have the purge port hooked up to anything; the line was hanging below the AC accumulator. After capping off the bowl vent port I hooked the purge line up to the ported vacuum on the carbs primary metering block. The big vacuum leak was supplying the air and the fuel was coming from a carb problem.
The carbs pervious owner had "modified" it by putting a sheet metal screw in the vacuum secondary linkage. I removed the screw before I did the rebuild but didn't make any adjustments to any of the other settings. The guy had also bent the linkage bar that prevents the secondary system from opening. The extra fuel for the fast idle was coming from the secondary idle circuit. The guy had ran the screw that controls the idle position of the secondary butterflies in so far that they were exposing the transfer slots all the way to the top. I now have a nice steady 700 RPM idle. If I back the idle set screw out it will go down to ~500 RPM in park. Now I’ve noticed an intermittent problem with the accelerator pump. Occasionally, the pump will hydraulically lock and compress the actuator arms spring when you work the throttle. Either a passage in the circuit is getting intermittently plugged or the needle valve under the squirter nozzle is getting stuck. More fun, lol…
There was a problem with the distributor mechanical advance. With the lightest set of springs the full advance wasn’t coming in until ~ 2800 RPM. I thought that was a little odd but let it slide. After rechecking the initial timing I could see that part of the mechanical advance was still in at idle, hmm… I pulled the rotor off to make sure nothing was binding and saw rub marks on the ribs of the rotor. After a little trimming, the advance is now all in by 2400 RPM and all out at idle. It’s also giving me the full advertised advance of 23 deg, so I might have to back the initial timing back a couple degrees.
I pulled it out onto a public road for the first time since 2005. My sole intention was to see how the trans shifted, so I was only going a 1/4 mile up the street and back. When I pulled in to turn around I heard a clunking sound from the front end and felt a little vibration. Doh… Loose lug nuts. The trans shifted fine and I limped it back home and pulled it into the garage. Time for a beer
It still needs exhaust before it can really hit the road.