Rochester 2bbl, et al - Impala Tech
Troubleshooting Diagnosing problems

 
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post #1 of 10 (permalink) Old 10-05-2012, 11:15 PM Thread Starter
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Rochester 2bbl, et al

Hi
Just had some electrical trouble with my 1962 Impala ( just solved!!!!) which is in a separate post in the Electrical section, but had some problems with the carb as well ( I thinks its the carb)

Its been a few years since I had run the car, went to the procedure, started the car,etc, all was fine ( besides the starting problem)
Drove the car around a bit would say about 200 yard back and forth several times.
Had noticed some fuel seeping thru the carb, no biggie.
Later that day we would put the car in drive and it would stall, right away, put it in reverse and it would stall, but in park or neutral at idle it would run fine.

Left it as it was, went back the next day and same thing.
Took the carb off, replaced gaskets and put it back on the car, noticed something funky with the idle/choke,etc..
Theres a rod at the bottom of the throttle that goes back in the firewall, that rod seemed to be in a position that held the idle ( the swivel snapped while removing the carb)

Again, the car did the same and now it was very hard to start, ( when I removed the car I tried not to mess with the settings)
I sprayed carb cleaner into the vacuums and all around with no changes at all
Also set the idle higher which seemed to improve (almost to how it was) but in drive.
If put in reverse the car hessitates and I have to kinda rev it so it will go backwards..( at least its not dying now)

Sorry for the long post but I want to be as specific as possible..

Any help?? Clues, knowledge...(all welcome)

Thanks in advance..

PS: I have not checked the plugs yet for coloration.

Last edited by Elchopperfreak; 10-06-2012 at 12:24 AM.
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post #2 of 10 (permalink) Old 10-06-2012, 07:47 AM
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I would check the timing and the points in the dist. Dwell would be 28-32. Also did you put fresh gas in it? Old gas doesn't burn very well even when mixed with new.
You might consider new cap, rotor, points, condenser, vacuum advance, plugs and wires.
A rebuild of the carb would also be in order after sitting a couple of years as gas that had dried up inside the carb causes corrosion and plugs up passages inside the carb.
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post #3 of 10 (permalink) Old 10-07-2012, 12:24 PM Thread Starter
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Looks like this is all the carb has for tuning, besides the idle???



Does anyone notice anything incorrect, im just double checking

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post #4 of 10 (permalink) Old 10-07-2012, 12:30 PM Thread Starter
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What is this bottom linkage?? When I removed the carb the swivel snapped, then again for what I could see by the firewall the other end is not attached

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post #5 of 10 (permalink) Old 10-07-2012, 12:57 PM
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Lower linkage is for Powerglide kick down. (Passing gear) From your photo it looks like you have a open vacuum line at the rear of the carb that needs hooked up or plugged.
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post #6 of 10 (permalink) Old 10-07-2012, 01:06 PM
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The lower rod is your down shift mechanism that connects to the transmission. Or as it was known by many drivers the "passing gear".

Those two screws control the volume of air that enters the carb's idle circuit to calibrate the air fuel mixture at idle. In is rich out is lean.

Your carb leaks gas because the car sat for a while and all of the gaskets dried out. That carb needs to be rebuilt to work properly. It will require a refreshing bath in carb cleaner; once it is disassembled. After that it can be rinsed out and dried off with compressed air before being reassembled with new gaskets and a new needle and seat. If that challenges your abilities you can buy one already rebuilt at most corner national chain auto parts stores.

Ignition issues are as complex as carburation issues and often mask each other in terms of symptoms. I would buy a replacement small cap HEI from the aftermarket and run new wires. No more dwell issues or hard starts due to low voltage to the plugs.

Big Dave
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post #7 of 10 (permalink) Old 10-07-2012, 09:39 PM Thread Starter
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Big Dave
Thanks
The "passing gears" was attached to the lower cam ( is that the right word?) my guess is that it worked as the idle, since the idle screw was completely off ( not even remotely touching)

I took plugs out today and they are a bit sooty, hence the carb is rich or not burning properly.

Tried to adjust the carb by the two front facing needles ( started at bottoming 1 1/2 turns) but there was no difference.

Already took the carb appart, cleaned everything as best as I could ( no bath yet) new gaskets, etc.. Nothing much, Ive learned from linkerts and Super Bs that the less you mess with them the better..( but I will do a complete rebuild)

My plan is getting new plugs in and adjusting the carb first, but I also think its time for new cap and rotor and some plug wires.

The thing is, the car was running fine last week, the bogging down while in gear happened suddenly ( im leaning to bad plugs)
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post #8 of 10 (permalink) Old 10-07-2012, 09:42 PM Thread Starter
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Dadstoy
Where does that vacuum heads to?? I believe its been like that since I got the car.
I can easily do either, plug it or connect it..

Thanks for the reply and video
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post #9 of 10 (permalink) Old 10-07-2012, 11:04 PM Thread Starter
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Heres the other side, seems like it never had the choke connected, besides that, what else is wrong?


What is the small knob with the spring for ( you can see like half of it t the far left of the screen)


Thanks again guys
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post #10 of 10 (permalink) Old 10-25-2012, 10:38 AM
 
 
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Quote:
Originally Posted by Elchopperfreak View Post
What is the small knob with the spring for ( you can see like half of it t the far left of the screen)


Thanks again guys
I believe that is the idle air bypass screw. I searched high and low for what it was too. I think it's for making very fine adjustments to the idle and probably won't make much difference if you are having major idling issues.
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