cutsupreme72

Hello All,


I recently rebuilt my Rochester 7043250 for my 72 cutlass supreme ( I know the carb is a 73 and the car is a 72) I originally rebuilt it as I saw a little fuel seepage and wanted to change the gaskets. I ended up changing the following items:


Rebuild kit
float
enrichment tubes
fuel line
choke coil and cover


I have the carb on the car and it runs nice in park and at idle. I adjusted the vacuum using the middle port on the manifold vacuum switch (which goes to the vac advance on the dist.) I adjusted idle screws and it smoothed out quite well. bounces a little when trying to get max vacuum (what I mean by this is that it isn't a clear fluid movement from 18-20 on the vacuum gauge) it bounces a little once my highest measurement is taken and it's difficult to gauge when I see the decrease but I got it as good as I could. I pushed the choke lever all the way to towards the top (where it would be after you pressed the pedal for a cold start) and adjusted the high idle (This may be my problem) warms up and stays at 1100 during idle. and goes to 650-700 in drive. I do remember the idle dropping to 650 when the engine warmed up and it doesn't do that anymore and I have verified that the choke is open once warm. I drive the car and it sits at about 700-800 on the tach but feels too fast ( I have to hold the brakes down as I'm driving as the idle is doing most of the throttle at this point. in drive at a stop it's a nice idle 650-7 take foot off brake and it climbs up. When I punch it, it has plenty of power but feels as if the trans is not kicking down properly. ( the trans shifted great and carb ran great before I meddled with it plugs are pretty new, hei is great shape, oil and fluids are new) Mainly I have a problem with it idling too high in drive wheels rolling, and some transmission hesitation (overrevving) when it's punched (not as smooth and crisp as it used to be) I have already accepted the if it ain't broke mantra and If I end up tossing this one in the future at least I got to tear it apart and learn the insides of these great carbs. Any help or suggestions would be a huge help. I am mechanically inclined (certified diesel mechanic ) great on outboards and EFI engines (however I'm a younger guy (my car is 11 years older than I am so I didn't grow up working on these guys like many of you have so your help is always appreciated!

oldcutlass

Your hi idle screw adjustment may be overriding your curb idle adjustment. Look to see if your curb idle screw loses contact with the saddle it rides against. In other words loosening the curb idle screw will not lower the idle speed anymore.


Depending on your cam, you may not get a steady needle on your vacuum gauge, however you have good vacuum @18-20. I would adjust for the best idle quality and monitor the gauge. Make sure your 2 a/f mixture screws are close to equal turns when setting. For example bottom count the turns from where they are while turning in until they lightly bottom and then back them back out to where you previously had them adjusted. This ensures your not running off of one side of the carb at idle.

cutsupreme72

Thanks oldcutlass! Curb idle is losing contact with saddle like you stated, it won't go any lower if I loosen it. So if I am understanding you correctly I need to back out the high idle screw a bit and equalize the idle mixture screws? Engine was rebuilt before I bought it and it was a good rebuild, runs great, reputable company here in southern cal, great compression and low miles (about 8k since rebuild) I'm pretty sure it's a stock cam, idle was near perfect before I tinkered with it (carb was also previously rebuilt as it has the sticker (factory tested quadrajet) Ruggles book says this may be a doable but more difficult rebuild. to clarify if it helps


I have a 350 rocket 350 trans
edelbrock performer 350 intake
HEI (pertronix)
dual exhaust
chrome air cleaner
chrome alternator
stock everything else

oldcutlass

Yes back the hi idle screw a bit and make sure the choke mechanism isn't hanging up by not dropping to the lowest step.

johnnyjaws

did u sonic clean or soak the carb to clear out all passage ways that might be plugged?