>have a 1971 Deville sedan>absolute stunner given the year>handles like a yacht>tasty 472ci. V8>runs rough, carb could do with a clean and rebuild>carb rebuild complete>install carburetor, fuel lines, vacuum lines>everything seems lined up to fire up>ignition applied>ladies and gentlemen, the boat no longer turns overA little history, she was running beforehand. Granted if she sat too long she'd need a lil starter fluid, nun serious. I rebuilt the carb, made sure the float and needle had range of motion, gaskets installed properly, air passageways as cleared out as I could get them, fuel line fitting replaced and reflared. Everything is hooked up properly, save for a single vacuum line that went to the airbox, she'd run fine normally with that vacuum line open. Pumping the throttle, you can see fuel being injected into the carb through the choke. I refilled (to the best of my ability) the fuel bowl through the fuel vent at the front of the carb, via an empty and dry water bottle.In THEORY, she should be turning over. She cranks, but even with starter fluid, choke shut (or open even), she got at most four proper firing rotations before dying out. I dont want to keep flooding her with starter fluid and killing the battery. Not sure what to try and diagnose, if anything, or if I should just keep trying to crank her over against her will.Any ideas?
Compression, spark, fuel, air.
>>28598141Assuming it's sparking evenly and you didn't fuck with the timing, it's gonna be a carb issue, which isn't as surprising as it sounds. Getting a quality carb rebuild kit is like getting points - these are garbage parts, built to service completely outdated systems. Get back into that Q-jet and take a good look at the new needle and seat and make sure they aren't fucked. Check the float level and get the correct measurements from a Chilton's manual or online or whatever. Not a Cad guy, but I THINK the 472s and 500s both use a big 800cfm carb.
>>28598141>she got at most four proper firing rotations before dying outGet a decent battery in it that'll spin the thing at a good speed for longer than 4 rotations. It's probably flooded now and it's gonna take some cranking to clear it.>if she sat too long she'd need a lil starter fluidQuadraBogs like to leak from the well plugs on the bottom of the venturi body. Most commonly the primary jet well plugs but can from the secondary too. Plenty of online documentation on this so you can find something that suits you to correct it.
>>28598141Off the top of my head:1) Disconnect fuel pump from carb, it should run fine with a liberal application of starter fluid. If it doesn't, you have a timing / spark issue (check firing order if you removed the spark plug wires).2) Check the spark plugs. If they're wet with fuel, you have a carb issue (also see below). If they're relatively dry, you might have a ignition issue. 3) Quadrajets are hard to fuck up, but I have ran into mis-seating the needles in the jets multiple times. If you don't install them correctly, it bends the needle and DUMPS fuel into the engine. You don't suspect it, and it's insanely difficult to diagnose as you're not expecting the carb to be constantly flooding. Check needle installation.
>>28598727>>28598635>>28598416I seriously appreciate the replies, I'll see about maybe getting a new battery or charging the one I have and giving her another go round. If that doesnt get the job done I'll yank the carb and take a look at those needles. Is there any way to diagnose mis-seated needles without tearing it all apart again? And would foreign materiel between the needles and jets cause a similar issue?
>>28598141>QuadrajetHoooo boy
>>28599069Stop bitching, wrenchlet.
>>28599002>Is there any way to diagnose mis-seated needles without tearing it all apart again?If the primary venturis are soaking wet that's usually a good sign of a flood-over. True for about any carb too, though with dual-bowl Holley's you can have secondaries wet while the primary is dry.>would foreign materiel between the needles and jets cause a similar issue?Yep. Again, see any Holley on the secondary side after its just been worked on lol.Another tidbit about 'Bogs. The air horn and venturi bodies warp, usually due to excess torque being applied to those front bolts, so you should check them with a straightedge whenever you have one apart. (Holley VB's and metering blocks too as everybody likes to be a gorilla on those fuel bowl screws)
>>28599002You could possible tap on the housing and see if it pops loose. The issue I'm seeing, more and more, it the needle and seat aren't even machined as well as the old one. Invert the entire top half of the carb, look under and see if the needle is actually dropping, when the float moves up and down. There are a FEW other things that can go wrong with a Q-jet, but they're generally on the secondary side and won't keep it from starting.
>>28598727>>28598635>>28598416>>28599081>>28599162Im off work finally. I found out the battery was completely dead, got it checked at NAPA, and subsequently replaced. I found a weird electrical-esque connection that slots into the throttle linkage that was not connected properly, and a vacuum line that was undone from a smaller capacitor lookin thing connected to the ignition coil.New battery in, vacuum line hooked up, weird rotating electrical connection hooked up. She cranks hard now, and with starter fluid she'll fire a few times before coasting down fairly quickly. I'll see about getting the carb off and looked at in the next day or so, to start going over some of the things y'all suggested. I'm also gon try and test spark if I have the time (anyone know a quick way that doesnt require removing spark plugs?). In case I dont update this thread any further and y'all are interested, just keep an eye out.
>>28599859Electrical connector is probably a high-idle solenoid. It kicks up the idle when the car is cold. Pull the plug wires, one at a time, have someone crank it, hold the coil wire near a ground and see if it sparks. You might have to stick a screwdriver in there to make sure the insulation doesn't get in the way.
>>28599077The best way to tune a Qjet is to replace it with a Holley.
>>28600634No, an edelbrock. Damn things will sit for years without gunking up
Got the carb off. Taken apart. I bent the float adjuster a bit so it actually had range of motion, when I rebuilt it initially the float seemed stuck between the needle and diagphragm. I bent it back to near original shape, if this aint the move, tell me. I've taken out the main metering rods, removed the little meter rod seats, and I've got eyes on the wells. Nothing seems out of place and I followed the rebuild instructions to the letter.The ball bearing is under the diaphragm where it should be. Is there a way to check that all the air and fuel passageways are cleared? I wont lie I've never dealt with carbs so all this shit is still relatively foreign to me, but I want to learn
>>28601558The carb in question. If anyone wants pictures of the metering rods, or any other component let me know, I'll happily provide.
>>28600634Sure, if you're dumb.
OP here: UPDATEShe runs just fine now, took the carb apart, cleared her out and she starts up no issue, didnt even need starter fluid starting it up a second or third time. Turns out I flooded that bitch when I filled the bowls pre-emptively with fuel via the fuel vapor vent. I appreciate the help y'all, turned out to be a lot simpler than I thought.
