Faulty Rochester 4GC??

[highcking]

My Roadmaster part-throttle stumbling has not yet been solved -- but now I may have an answer. Several folks on this forum suggested pulling the "rebuilt" Rochester 4GC and taking a close look at the primary throttles. I did this and found something I can't explain. One of the primary barrels seems to have no idle orifice. The other primary barrel does and there are idle orifices in each of the the secondaries. I looked very closely to see if the orifice was simply obscured or blocked up, but I don't think so. It's not there.

Anyone ever see this? Every 4-barrel I have has an idle orifice in each primary barrel. Otherwise why have two idle mixture screws? Could this be a factory defect? It certainly explains why the mixture is too lean until the throttle is open pretty wide.<!-- google_ad_section_end --> Only one idle feed is active. I can't find any reason to believe this is the way the carb was designed.

[60FlatTop]

There shouldn't be idle circuits in the secondaries. Part throttle stumbling might be related to the power valve, but more likely plugs or wires.

Watch the fuel flow while the car is running. Do you get a good shot of fuel from the accellorator jets when you blip the carb? I had a 4GC that shot out good when not running but had no fuel when it was running. Write me if you find that.

Sometimes plugs and new fuels don't get along. Get them a little wet from flooding once and they don't recover. Put in a fresh set of AC 45's. I've had a couple that just refuse to run unless they get fresh plugs.

Bernie

[Smartin]

Are you running points?