Rochester 2GC questions
#1
Rochester 2GC questions
So, a friend of mine's brother in law, who is a professional mechanic, helped me rebuild my carburetor recently, back in December. It's a lot better than it was, but I still get stalling issues at take off. I recently had my heads redone and intake manifold refinished, so there are no vacuum leaks at the manifold. My fuel pump is tested good. I did a proper tune-up on it not too long after I first got it about a year ago. I used Bosch Platinum Plus plugs, new wires, new cap, rotor, I've set the dwell and timing to the correct spec, and set the idle mixture screws to maximum vacuum. I'm getting 20-22in of vacuum according to the gauge. Advancing the timing seems to help a little bit. I really don't know what else to try. Perhaps some adjustments can be made on the carburetor? The only thing that stands out is my float. We didn't replace the nitrophyl float which sometimes is known to absorb fuel according to a few carb rebuilding shops. I didn't see him measure the float drop either.
My mileage has been exceptionally poor. Maybe 4mpg in the city, a little better on the highway, not putting my foot in it at all.
Another thing to note is that I am getting surging issues on occasion at certain speeds, and engine vibration at speeds over 50.
The goal here is to get rid of the car stalling when I put my foot on the floor.
Please help! I just want to drive my car.
My mileage has been exceptionally poor. Maybe 4mpg in the city, a little better on the highway, not putting my foot in it at all.
Another thing to note is that I am getting surging issues on occasion at certain speeds, and engine vibration at speeds over 50.
The goal here is to get rid of the car stalling when I put my foot on the floor.
Please help! I just want to drive my car.
#2
I've driven and rebuilt a few 2GCs, but that was a long time ago, and I don't claim any special expertise, but that float sure sounds like it could cause all your problems -
Heavy float, not adjusted when rebuilt, loads up with fuel too easily, gives poor mileage.
Another thing to consider is the accelerator pump - if the plunger, the spring, or the check ***** and springs are bad, they can cause stalling on acceleration in exactly the opposite way (momentary fuel starvation).
Having both problems is not out of the question.
The engine vibration could be a lot of things (including a bad fuel pump, or obstructed or pinched line), but fixing the stalling problem will at least eliminate one possibility.
I agree that with your symptoms, the first place I would look would be the fuel system.
One question - if you put your foot into it gradually, does it take off with your foot on the floor? Or does it misbehave then, too? That'll tell us more.
- Eric
Heavy float, not adjusted when rebuilt, loads up with fuel too easily, gives poor mileage.
Another thing to consider is the accelerator pump - if the plunger, the spring, or the check ***** and springs are bad, they can cause stalling on acceleration in exactly the opposite way (momentary fuel starvation).
Having both problems is not out of the question.
The engine vibration could be a lot of things (including a bad fuel pump, or obstructed or pinched line), but fixing the stalling problem will at least eliminate one possibility.
I agree that with your symptoms, the first place I would look would be the fuel system.
One question - if you put your foot into it gradually, does it take off with your foot on the floor? Or does it misbehave then, too? That'll tell us more.
- Eric
#4
I'd check that accelerator pump and the little ball(s) and spring.
If good old what's-his-name didn't bother to set the float height, I wouldn't be super confident in the rest of the work he did. That's a really basic and important setting.
- Eric
If good old what's-his-name didn't bother to set the float height, I wouldn't be super confident in the rest of the work he did. That's a really basic and important setting.
- Eric
#6
They usually come with the little check ball or ***** (I don't remember if it was 1 or 2), and the needle and seat, but not the float.
Also a little tiny cardboard, graduated measuring square, gaskets, accel pump piston, and a bunch of tiny clips to replace the ones you lose or break .
- Eric
Also a little tiny cardboard, graduated measuring square, gaskets, accel pump piston, and a bunch of tiny clips to replace the ones you lose or break .
- Eric
#7
So, a friend of mine's brother in law, who is a professional mechanic, helped me rebuild my carburetor recently, back in December. It's a lot better than it was, but I still get stalling issues at take off. I recently had my heads redone and intake manifold refinished, so there are no vacuum leaks at the manifold. My fuel pump is tested good. I did a proper tune-up on it not too long after I first got it about a year ago. I used Bosch Platinum Plus plugs, new wires, new cap, rotor, I've set the dwell and timing to the correct spec, and set the idle mixture screws to maximum vacuum. I'm getting 20-22in of vacuum according to the gauge. Advancing the timing seems to help a little bit. I really don't know what else to try. Perhaps some adjustments can be made on the carburetor? The only thing that stands out is my float. We didn't replace the nitrophyl float which sometimes is known to absorb fuel according to a few carb rebuilding shops. I didn't see him measure the float drop either.
My mileage has been exceptionally poor. Maybe 4mpg in the city, a little better on the highway, not putting my foot in it at all.
Another thing to note is that I am getting surging issues on occasion at certain speeds, and engine vibration at speeds over 50.
The goal here is to get rid of the car stalling when I put my foot on the floor.
Please help! I just want to drive my car.
My mileage has been exceptionally poor. Maybe 4mpg in the city, a little better on the highway, not putting my foot in it at all.
Another thing to note is that I am getting surging issues on occasion at certain speeds, and engine vibration at speeds over 50.
The goal here is to get rid of the car stalling when I put my foot on the floor.
Please help! I just want to drive my car.
#8
Well, I replaced the float this evening, and while I had the carburetor off I looked over a few things...apparently, the accelerator pump check ball was missing, and the wrong gasket was used.
Put it all back together, and set the float drop and float level by the instructions in the factory manual...the result?
...nothing but squealing tires when I stomp the gas
It dieseled a little when I shut it off though, which makes me think I had the timing advanced too far as a result of trying to compensate for the carburetor. I'll correct it tomorrow with the proper tools. Too dark out there now.
Put it all back together, and set the float drop and float level by the instructions in the factory manual...the result?
...nothing but squealing tires when I stomp the gas
It dieseled a little when I shut it off though, which makes me think I had the timing advanced too far as a result of trying to compensate for the carburetor. I'll correct it tomorrow with the proper tools. Too dark out there now.
#10
Just to be clear here, there's two things that'll help you out.
The first one is this video set:
Part 1. http://www.youtube.com/watch?v=6RTf2yrGcA4
Part 2. http://www.youtube.com/watch?v=-N0nH3n-f0E
Part 3. http://www.youtube.com/watch?v=uF-rK0Z2_Ec
Part 4. http://www.youtube.com/watch?v=Fa9YU4Rz8JA
Part 5. http://www.youtube.com/watch?v=549JhJkUhn0
Part 6. http://www.youtube.com/watch?v=zoGXDAA9WgY
The other I would suggest following is the factory manual for the float drop.
What I did was clean the car bout in the garage, then wiped it down good, brought it in the house under the nice lighting with the manual and got to work reassembling. Even better if you have a laptop you can put on the table and watch the video alongside your rebuild.
Also, if you can, buy that brass float if yours doesn't have one. It's just a good idea.
The first one is this video set:
Part 1. http://www.youtube.com/watch?v=6RTf2yrGcA4
Part 2. http://www.youtube.com/watch?v=-N0nH3n-f0E
Part 3. http://www.youtube.com/watch?v=uF-rK0Z2_Ec
Part 4. http://www.youtube.com/watch?v=Fa9YU4Rz8JA
Part 5. http://www.youtube.com/watch?v=549JhJkUhn0
Part 6. http://www.youtube.com/watch?v=zoGXDAA9WgY
The other I would suggest following is the factory manual for the float drop.
What I did was clean the car bout in the garage, then wiped it down good, brought it in the house under the nice lighting with the manual and got to work reassembling. Even better if you have a laptop you can put on the table and watch the video alongside your rebuild.
Also, if you can, buy that brass float if yours doesn't have one. It's just a good idea.
#11
Just an Olds Guy
Join Date: Jul 2008
Location: Edmonton, AB. And "I am Can 'eh' jun - eh"
Posts: 24,525
My car originally had a 2GC, which was ok but not great. It tended to have starting problems and a lag on acceleration just about all the time. Mileage was ok. After watching some of this video I would guess that the carb was probably not set right when it was built. Now I feel inspired to go out and rebuild it after I finish doing my front end. I won't put it back on the car - just something to play with.
#12
Well, I was dead set on making this carburetor do its job. Not too bad for roughly $25 in a new kit and a float from the auto parts store.
It's funny how necessity is the mother of invention. In better times I probably would have bought an EFI system and installed it with an electronic distributor. As a result of necessity. my goals have changed from upgrades to just making everything run as it was originally intended, then eventually when I have money I will add on.
It's funny how necessity is the mother of invention. In better times I probably would have bought an EFI system and installed it with an electronic distributor. As a result of necessity. my goals have changed from upgrades to just making everything run as it was originally intended, then eventually when I have money I will add on.
#13
Just an Olds Guy
Join Date: Jul 2008
Location: Edmonton, AB. And "I am Can 'eh' jun - eh"
Posts: 24,525
In better times I probably would have bought an EFI system and installed it with an electronic distributor. As a result of necessity. my goals have changed from upgrades to just making everything run as it was originally intended, then eventually when I have money I will add on.
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