FINALLY we are back out on track following our rebuild, and mostly the car ran very well. Tim got his first race in, and by tomorrow should be one step closer towards pulling off those x's. He had very good drives today, and by the end of his race today was turning laps within 6.5 secs of the ITS leaders. That said we did have some fuel delivery issues, and I had a couple of questions.
I'm not sure we have the floats set properly on the SU's. As I understand it when the floats are set properly with the suction chamber/piston removed you should be able to see the fuel just below the bridge/nozzle interface down in the carb. I can only see the fuel in our nozzles if I open the chokes up. Additionally, I have to have the mixture nozzles turned as far rich as they will go to get enough gas for the car to run, and I still think it's a bit lean with them there. I CAN'T make it too rich with the mixture knobs. As it's set though we seemed to make good power until Tim was winding it out where it would lay down a bit at higher revs.
One last quirk was that a couple of times we had fuel overflow the bowls out the float lid vent. Is it possible to overflow the bowls, and have the floats set too lean at the same time? This would happen coming off of power where the fuel was backing up in the bowl. My guess on this was that fuel pressure was too high (4.5-5lbs) so we turned it down to 3.5 lbs, but haven't run at that setting.
The carbs are z-therapy units, and are in very good shape. Timing is at 34 deg total advance, and the ignition is working well. Plugs come out with a good burn on them, and there are no vaccum leaks. What really has me miffed is that I can't get meaningful adjustment in the mixture knobs. At full rich setting it runs, and anything else is too lean to even hold an idle. Any tips with this is greatly appreciated.