Wait-what..... spread bore plate? Did you have a 4300D spreadbore carb and is that what you have for an intake?well I bought a new Holley 600 carburetor and slapped it on.
primed it and stared it up, it started and revved to 2500+rpm shut it off instantly.
checked for fuel leaks, then checked the curb idle was all the out just barely touching,
air mixtures were 1.5 turns out. Started it again same thing.
Loosened up the choke, disconnected the power.
Turned the choke clockwise to the last line. started again same thing revved to 2500rpms.
Turned it past the line about an inch started and it was barely running.
Brought it back a little and again revving around 2500rpms shut it instantly.
the fast idle screw is such a PITA to get to I think I will pull the carb off and see if it is causing the issue. so freaking aggravating. if I was back in my 20's one of those carburetors would of got the sledgehammer. my patience is better 30 years later but not much.
what do you think, could it be the fast idle causing this?
also it has a spread bore plate on it can I use the open gasket that came with the Holley or do I need the spread bore gasket? I have 2 sets of each.