Buick newbie with '69 430 running problems!

When you say “doesn’t reset automatically” do you mean it stays high until you blip the throttle?

That is totally normal and us old people grew up with it so we are used to it. It just a mechanical system and real driving would bring it down too. There is also a high idle adjustment screw to set the RPM.

It’s also common to find the choke mis-adjusted as the “adjustment” is bending the linkage rod. Even in the old days lots of mechanics couldn’t do this right.

 

I wouldn't bother doing any trouble shooting, email Quadrapower LLC, have them build you a new carb. Just had them do one for a '70 455 I'm going to drop into a '75 2 door Regal. They did a great job...12 weeks, mine took 16. Forget about the time it takes and how much it costs, I wouldn't even bother sending the old one to them, they can date code one of their cores to within a week or so of your original one, if it is, after all these years who knows. You'll be way ahead, there's a lot more wrong with your carb. than you realize. In the mean time change out the fuel pump, replace the PCV, clean out the fuel pump to carb. line, replace all the vacuum/emission lines, especially the one that connects that steel vacuum tube to the trans. modulator, change the valve cover gaskets, water pump bypass hose(you can get all three molded hoses[water pump/valve cover to air cleaner breather/PCV], from various vendors and clean the entire air cleaner assembly. But before you remove your old carb., pour a can of Chem-tool into 1/2 tank of gas and run most of it through the fuel system. Put new gas in, run some of that through, then remove the old carb, stand 20' from a metal trash can and see if you can throw it in on the first try. Then pull the radiator, fill it full of boiling water and a can of that radiator flush stuff, let it sit for a week, drain it, haul it to the car wash and spray all the bugs and s**t out of the fins, care full not to get water in the trans. cooler(if it's one of those aluminum ones with the plastic tanks, your allowed to stand 10' closer to the metal trash can while you attempt to throw that in there), change out the water pump/fan clutch, put on all new belts and hoses, coolant, thermostat, use permatex grey hi-tork RTV on the gaskets. Remover all the pulleys/fan and clean all the dirt/debris that may have accumulated in/on them, change-out the altenator if it's old. Change the motor oil/filter and be sure to use a brand of motor oil that comes in a container the same color as the paint on your car, filter make and color doesn't matter If you find yourself getting bored during all of this you may want to try creating your own weight of motor oil by mixing various ones together, personally I prefer 13.5 W 36 3/5ths semi-non synthetic. If you got some time left before the new carb. arrives, service the transmission, change-out the points/cap/rotor/spark plug wires and plugs(use platinum ones if available), multi electrode ones make no difference. Lastly get one of those reward cards from the local(insert national auto parts chain store name here), your going to need it. And if all goes well in about a year or so you'll have to change either the battery/starter/power steering pump/wiper motor, and wait until you get to do a heater core, if you haven't already. And whatever you do, don't pay to have nitrogen put in your tires Been there done all of this routine several times in 40+ years, by the way hi from Carson City NV, I'm new to this forum...thought I'd add my .02 cents.