Carb rebuild problems
07-06-07, 04:15 PM
#1
The Bridgy goes BRAP BRAP
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Carb rebuild problems
I just rebuilt my carb on my 84 GS. Now when I turn the key to "on" it starts to POUR gas into the carb... I can't figure out what's going on. the floats are fine it seems but its still filling up with gas I think... I've taken it apart 4 times already and everything is looking okay. I just can't figure it out. It also seems that the throttle linkage is binding on a spring or something. It isn't smooth and for some reason I can't mount the throttle cable because it isn't lining up! ARGH! help?
07-06-07, 07:49 PM
#2
I'd recheck those float levels, also look at the float valves and see that they are seating properly. The gas shouldn't pour into the carb when you turn the key on, this means something between the fuel pump and the jets is not holding the pressure of the fuel pump. That's about all I know, good luck.
Ray
Ray
07-06-07, 08:52 PM
#3
as Ray mentioned, this usually maeans that the floats are adjusted improperly or stuck. the floats are supposed to riise and cut the fuel off when the fuel reaches a certain height in the bowls. you will want to pull the top of the carb back off and recheck the floats and the needles and seats. make sure everything is installed properly.
07-06-07, 09:04 PM
#4
82, 83, 88, 82 RX-7again!
I just rebuilt my carb on my 84 GS. Now when I turn the key to "on" it starts to POUR gas into the carb... I can't figure out what's going on. the floats are fine it seems but its still filling up with gas I think... I've taken it apart 4 times already and everything is looking okay. I just can't figure it out. It also seems that the throttle linkage is binding on a spring or something. It isn't smooth and for some reason I can't mount the throttle cable because it isn't lining up! ARGH! help?
Scott
07-06-07, 09:26 PM
#5
The new needle valves have a very thin coating from the factory. The coating will wear off from use. Once you set the float level, work them up and down about 50 times each. Sometimes even this won't quite do it, and they still stick for a little while after your car is running. In this case, just give the carb a tap with the fat side of a screwdriver on the top.
Another important thing is to be very careful when you adjust the tabs on the floats. You will be apt to use needle nose plyers. They work great but the teeth will leeve very small grooves in the float tabs. The valve spring arm will get caught in the grooves and not opertate smoothly. This can cause them to stick and the bowl will flood. Get a piece of sand paper and make them nice and slick after you get them adjusted.
Your binding linkage is likely the result of a bolt not being tight or the linkage was assembled wrong. I did both when I rebuilt mine, so don't feel bad. Take the carb off and work the linkage with your hand. Look at it from every angle as the butterflies open and close. Check every mounting bolt twice.
Good luck.
Another important thing is to be very careful when you adjust the tabs on the floats. You will be apt to use needle nose plyers. They work great but the teeth will leeve very small grooves in the float tabs. The valve spring arm will get caught in the grooves and not opertate smoothly. This can cause them to stick and the bowl will flood. Get a piece of sand paper and make them nice and slick after you get them adjusted.
Your binding linkage is likely the result of a bolt not being tight or the linkage was assembled wrong. I did both when I rebuilt mine, so don't feel bad. Take the carb off and work the linkage with your hand. Look at it from every angle as the butterflies open and close. Check every mounting bolt twice.
Good luck.
07-06-07, 09:45 PM
#6
Airflow is my life
If the float setings are ok then you might wana try this. Add a drop of oil to the needle tips and also to the float axle/pivot points. Sometimes they stick initially after rebuild. This tends to help them seat. Also the metal parts of the floats are very delicate and can end up misaligned easily if you bend them at all. And dont put any scratrches on the tab that contacts the needle. It can cause it to catch and not work properly. I use a special smooth toothless needlenose to make this adjustment.
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07-07-07, 12:36 AM
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The Bridgy goes BRAP BRAP
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ok... so... it isn't pouring gas into the carb anymore... but now... it won't start unless you pour fuel down the carb... whats wrong?!!
07-07-07, 12:14 PM
#10
When you rebuilt the carb, did you blow carb cleaner or compressed air through every passage? Did you make sure the small ***** and spacers were placed in the correct order?
Also, if you are using the Haynes manual the float height is printed wrong in the book. The procedure is correct but the correct measurement is in the Factory Service Manual.
Also, if you are using the Haynes manual the float height is printed wrong in the book. The procedure is correct but the correct measurement is in the Factory Service Manual.
07-07-07, 03:15 PM
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So... one side is perfect... the other side is either way too high or way too low... even with the smallest adjustment, it changes SO much 
I'll never get it at this rate :/
I'll never get it at this rate :/
07-09-07, 01:22 AM
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OK so now, its all good and stuff but, when I run out 1st and 2nd and shift into 3rd, it bogs like crazy and then won't drive smoothly for a minute or so, like it ran out of gas.. then it drives fine. Does the same thing going up big hills :/ What could possibly be the problem?
07-09-07, 11:40 AM
#15
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I never recommend that someone change their float level settings to stop fuel from pouring into the carb. It's impossible for the float levels to be adjusted for this to happen.
However, if the tab on the float that actuates the needle is bent, this can happen.
The floats should not ever have to be adjusted. They were adjusted at the factory, and unless they've been mishandled, they haven't changed their settings. But once they are messed with, it can be difficult to get them back to where they should be, especially if the center tab has been tweaked.
Fuel pouring into the carb is indicative of either a needle not seating, or the float bowl solenoid malfunctioning. The float bowl solenoid rarely malfunctions; it usually has to soak in water and get a bit of rust in there for that to happen. But if there's no current to it, the plunger stays closed and there's no vent to the carburetor fuel system. Gas comes in but the bowl air pressure increases and wreaks havoc with the floats. if one float doesn't close all the way, the fuel continues to pour in and fill that bowl up. It then fills the other bowl up through the vent circuit in the air horn before eventually spilling directly into the carb.
The same thing happens if one float needle doesn't seat. A needle may not seat after a fresh rebuild because the brass needle has a matte finish to the surface, possibly applied by vibratory polishing, a usual industrial mass finishing process. If you make an effort to burnish all four corners of the needle valve shaft, it will slide in and out without binding. The fuel acts as a cleaner and has an anti lubricating effect, so even though this matte finish seems like it would give a minuscule amount of friction, it's just enough.
Never cram the needle deep into the seat. This accelerates the wear on the rubber needle tip, and lowers the longevity of it. The wear on your old needles takes the form of a noticeable ring around the rubber tip where the material has been compressed. When the ring forms, it lessens the needle's ability to plug the seat effectively, and you begin to get driveability issues, and poor fuel mileage, if not outright flooding problems.
After a rebuild, it's very common for the needles not to seat correctly. But if you've burnished the needle brass, then all that should be necessary is a few taps over the offending float bowl with a screwdriver handle. Once the valve starts functioning properly, you should not have to repeat this. If you find that the needle frequently does not close, chances are you have a debris problem.
Kitsune, the accelerator pump is malfunctioning, and that's what's causing your bog. Look down into the carb with the engine off, and operate the linkage. You should see two streams of fuel shoot into the carb; one into each primary venturi.
The fuel for the accelerator pump comes from the firewall side fuel bowl, so with the engine off, if you've squirted the accelerator pump several times you'll deplete the fuel in the bowl and you'll need to turn the key to fill up the carb again.
Do not remove the nozzle with the carb on the car. You cannot access the check ball and weight this way anyhow because you'll need to turn the carb over for them to fall out. But if the other part of your pump is working correctly and you operate the linkage with your nozzle off, you'll blow the weight and check ball out of the carb and probably lose it -maybe even down the carb and into your engine!
Check to see if the diaphragm inside the accelerator pump housing is springing forward. If you misplaced or forgot the spring behind the diaphragm, the accelerator pump won't be able to suck in any fuel when the throttle is let off. It can, however, fill up under certain driving circumstances because of pressure built up in the fuel bowl right behind the pump (the pump's source of fuel). So it can work "sometimes", but not when you need it.
The accelerator pump should be adjusted so that the vertical line of the pump lever - the part that pushes on the diaphragm pin, is parallel with the vertical lines cast into the housing cover that form the lever fulcrum slot.
However, if the tab on the float that actuates the needle is bent, this can happen.
The floats should not ever have to be adjusted. They were adjusted at the factory, and unless they've been mishandled, they haven't changed their settings. But once they are messed with, it can be difficult to get them back to where they should be, especially if the center tab has been tweaked.
Fuel pouring into the carb is indicative of either a needle not seating, or the float bowl solenoid malfunctioning. The float bowl solenoid rarely malfunctions; it usually has to soak in water and get a bit of rust in there for that to happen. But if there's no current to it, the plunger stays closed and there's no vent to the carburetor fuel system. Gas comes in but the bowl air pressure increases and wreaks havoc with the floats. if one float doesn't close all the way, the fuel continues to pour in and fill that bowl up. It then fills the other bowl up through the vent circuit in the air horn before eventually spilling directly into the carb.
The same thing happens if one float needle doesn't seat. A needle may not seat after a fresh rebuild because the brass needle has a matte finish to the surface, possibly applied by vibratory polishing, a usual industrial mass finishing process. If you make an effort to burnish all four corners of the needle valve shaft, it will slide in and out without binding. The fuel acts as a cleaner and has an anti lubricating effect, so even though this matte finish seems like it would give a minuscule amount of friction, it's just enough.
Never cram the needle deep into the seat. This accelerates the wear on the rubber needle tip, and lowers the longevity of it. The wear on your old needles takes the form of a noticeable ring around the rubber tip where the material has been compressed. When the ring forms, it lessens the needle's ability to plug the seat effectively, and you begin to get driveability issues, and poor fuel mileage, if not outright flooding problems.
After a rebuild, it's very common for the needles not to seat correctly. But if you've burnished the needle brass, then all that should be necessary is a few taps over the offending float bowl with a screwdriver handle. Once the valve starts functioning properly, you should not have to repeat this. If you find that the needle frequently does not close, chances are you have a debris problem.
Kitsune, the accelerator pump is malfunctioning, and that's what's causing your bog. Look down into the carb with the engine off, and operate the linkage. You should see two streams of fuel shoot into the carb; one into each primary venturi.
The fuel for the accelerator pump comes from the firewall side fuel bowl, so with the engine off, if you've squirted the accelerator pump several times you'll deplete the fuel in the bowl and you'll need to turn the key to fill up the carb again.
Do not remove the nozzle with the carb on the car. You cannot access the check ball and weight this way anyhow because you'll need to turn the carb over for them to fall out. But if the other part of your pump is working correctly and you operate the linkage with your nozzle off, you'll blow the weight and check ball out of the carb and probably lose it -maybe even down the carb and into your engine!
Check to see if the diaphragm inside the accelerator pump housing is springing forward. If you misplaced or forgot the spring behind the diaphragm, the accelerator pump won't be able to suck in any fuel when the throttle is let off. It can, however, fill up under certain driving circumstances because of pressure built up in the fuel bowl right behind the pump (the pump's source of fuel). So it can work "sometimes", but not when you need it.
The accelerator pump should be adjusted so that the vertical line of the pump lever - the part that pushes on the diaphragm pin, is parallel with the vertical lines cast into the housing cover that form the lever fulcrum slot.
07-09-07, 08:36 PM
#16
The Bridgy goes BRAP BRAP
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The accelerator pump is fine... We made sure it worked.
The car is bogging at full throttle after running through 1st through 3rd. It isn't getting enough gas.
On the way home, I was doing ~70 the whole way and after about 70 miles it started to act like it was out of gas (bucking and unresponsive to throttle). I put in the clutch and let it idle for like 15 seconds and then it drove normally.
What would cause the float bowls to not replenish themselves fast enough causing fuel starvation?
The car is bogging at full throttle after running through 1st through 3rd. It isn't getting enough gas.
On the way home, I was doing ~70 the whole way and after about 70 miles it started to act like it was out of gas (bucking and unresponsive to throttle). I put in the clutch and let it idle for like 15 seconds and then it drove normally.
What would cause the float bowls to not replenish themselves fast enough causing fuel starvation?
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