So, yeah I'm new here - been poking around for a little bit. I've got a carb question for you all - I've got a 1962 Coupe DeVille, 4-barrel (Rochester, I believe). She ran like a champ for a week after coming out of storage... Then basically overnight, she idles very very rough in gear, a little less rough in park - hesitates upon acceleration and surges. At first I thought it was the float, but now I'm thinking the accelerator pump. Because the issue happened so quickly, I can't also help but think a vacuum line might have failed on me... Any thoughts you might have would be greatly appreciated.
First off, Welcome! Nice Cadillac too! How long was the car in storage? Do you have "old" gas in the tank?
Thanks! So the car sat at a shop for the last 6 months (disc brake conversion that took way way too long) - basically the car sat unmoved, just shuffled around the shop a few times but that's all. It's got fresh gas (Premium + lead additive). Problem occurs regardless of engine temp... or length of operation. Exhaust is really rich - it's totally bogging down. which I why I thought it was the float -- but I think a vacuum problem could cause the choke to act up, pushing more gas than needed. Thoughts?
Pull air cleaner block choke open what happens then? With choke open and idling look down carb with a flashlight see and fuel dripping?
The cost of a rebuild kit is cheap and you'll probably end up solving another problem that could pop-up. I'd rebuild the carb and replace the vacuum lines with new ones and make sure your fuel lines are run properly.
First think I'd do is replace all the vacuum lines. Old lines get old and crack or sometimes swell and loose their connection on the nipples. (happens to me sometimes too ). If that dont fix it, it may be time for a carb rebuild. Gaskets can dry out and shrink.
You can trouble shoot a vacuum hose problem with a good sized pair of needle nose pliers. With the car running poorly pinch off each vacuum hose that comes off of the carb and or the intake manifold including the power brake booster. If you have a bad hose or a leaky diaphram somewhere in the car, the engine will pick up when you pinch the offending hose closed eliminating the vacuum leak. That will tell you where to look. If nothing changes, I'd look else where before going on a wild goose chase. I'm betting there are an ass load of vacuum hoses on that boat.
Thanks all - After more research, turns out it's a Carter carb (rather than a Rochester) - not that would have much impact on my issue. Tommy - your plier test sounds like a good start. That's my first step.
I once rebuilt the Rochester 2bbl carb in our Olds with an NOS rebuild kit and it ran with similar symptoms that you describe. It turns out that the accelerator pump was old and had actually crumbled in the well. A $12 kit from OReilly's fixed it right up. I know it's a different carb than yours, but the same principles may apply...
Update - ended up having Weimer Machine rebuild the carb. After inspection it was apparent that it was all gunked up needed a good bath. Also installed an electronic choke and a second fuel filter before the fuel pump to catch any more of the mystery black junk that kept clogging the temperamental glass bowl filter (and trying to avoid damage to the pump itself). While my wallet took a hit, it's nice to be behind the wheel again. So all is well again - in fact she's running better than ever.
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