Pop goes the carb

Post date: Sep 17, 2012 7:00:03 PM

Another weekend down, but not much progress. I think I tore down that carb about 10 times. Tried two different bodies, two throttle plates, just one air horn. Lots of combinations of idle tubes, jets, rods, APT setting, etc. Drivability has gotten pretty good, but just can't get a solid idle. It's currently running about 1200 in neutral in order to get 750 in drive. I did, at one point, have a good combo that idled really solidly at 700 and went to 900 in neutral. Of course I didn't take notes. That setup was way too rich everywhere else, so I moved away from it. Hm. One interesting aspect is with my old 7042250 body, the best idle is with the screws about 3 turns out. With a 7042251 with the same modifications, the idle screws need to be 5+ turns out and still seems to need fuel. Something ain't right there. The problem with the 7042250 is I made some "interesting" modifications to it back in the day, so I'd rather not use it permanently.

It doesn't help that I'm still not 100% confident in the ignition system. I also burned through the #8 spark plug wire - it was pushing on the header. Decided I must need 90deg boots. Well, those don't fit well at all due to the odd angle of the spark plugs on these heads. So I'll need 45deg boots. That'll be spark plug wire set.... 6? Yeesh. After that, I switch back to the HC coil but it still fired intermittently. Gotta try to get that replaced.

I also hit a situation where only #1 and #7 were crazy rich, all the others looked great. Those are on the same plane in the intake. Maybe the idle fuel distribution is completely hosed? Hmmmm....

I did get another 50 miles on it. It did lean out and did one quick backfire while going up an extended light grade against the wind on the freeway. That was exciting. Pulled over to richen the APT and saw the headers were bluing. Toasty. I did *not* hear any pinging, though. I tried to induce pinging - I think the vacuum can is pulling close to 12 deg - and simply couldn't. That was a huge relief. Always a chance that the exhaust leaks are covering it up, but I don't think so.

In other news, I wired a grounded 30A 240V outlet by my workbench. The bench now plugs into that, uses one phase for all my bench outlets and has an ungrounded 30A on the front for the welder. I reminded myself how much I hate working on exterior walls in the attic - at least there wasn't any insulation to deal with!! - and only made one big mistake. Easy to see what you did wrong when sparks fly, at least. But, fixed that all up and now it's great. And I'll be ready if (hah, when!) I ever get a bigger compressor.