No acceleration

[cabbie]

Hello,

I've had a recent problem develop on my 63 (340hp, original carter carb). When I start from a dead stop, it feels like I'm in 3rd or 4th gear instead of first. I have to really floor it to keep it from stalling out. Once going, it runs kinda rough and has no power. It will occasionally run normal for a few seconds, but then goes back to having no power. I've recently had the carb rebuilt as well as replaced the exhaust manifolds and heat riser. It seems to idle OK, just doesn't have any power. Any thoughts on whats causing this/what I should try to fix it? Thanks.

 

[IH2LOSE]

Hello,

I've had a recent problem develop on my 63 (340hp, original carter carb). When I start from a dead stop, it feels like I'm in 3rd or 4th gear instead of first. I have to really floor it to keep it from stalling out. Once going, it runs kinda rough and has no power. It will occasionally run normal for a few seconds, but then goes back to having no power. I've recently had the carb rebuilt as well as replaced the exhaust manifolds and heat riser. It seems to idle OK, just doesn't have any power. Any thoughts on whats causing this/what I should try to fix it? Thanks.

Welcome to the forum.Sounds as though the primaries may not be putting fuel into your carb,I am not so falmilur with carter Carbs but I would take the air cleaner off (with the car off) and llok into the throat of the carb and depress the throttle to see if any fuel squirts in.

Who did the carb rebuild?

Did you change the fuel filter also

 

[wishuwerehere82]

It could be the accelerator pump on the Carb.

No squirts mean no power on acceleration from idle to the power circuit for the fuel.

 

[IH2LOSE]

It could be the accelerator pump on the Carb.

No squirts mean no power on acceleration from idle to the power circuit for the fuel.

You know I had this same problem after I installed a distributor in my 66 and was sure it was related to the distibutor what I had found was that a hose was not allowing the accelerator pump to work.Excellent place to start looking

 

[JohnZ]

If the heat riser valve is on upside-down (it can easily be installed that way), it won't open, and all the right side exhaust is forced through the narrow crossover passage and out the left side, and there's hardly any power at all. Worth a look. The arm with the weight on it should be level with the engine off and cold, and should swing 90 degrees DOWN when you push on it; if it only pushes UP, it's on upside-down.

 

[cabbie]

Well, I checked the heat riser and it is installed correctly. Fuel is squirting into the carb on acceleration, so that seems ok as well. I am in the process of changing the fuel filter, but am having some problems attaching the new filter. I can't get it to keep from leaking on either end. I've put some sealer on the threads, but it still seems to leak. Any tips on how to keep it from leaking? Any suggestions on the sealer I should use on the threads? I'm thinking the sealer I'm using may not be setting well enough.

Thanks for all the tips so far.

The carb was rebuilt by a recommended mechanic in upstate new york. He works on a lot of classic cars, and has done great work on mine. I've now moved the car to New Jersey so I am unable to take to him to check, and I haven't found a new mechanic in my area yet so I'm trying to see if I can get to the root of the problem myself.

 

[magicv8]

Possibilities:

1 If you had the distributor out and worked on it, the gear could be backward.

2 If you havent cleaned the mechanical advance mechanism lately, it may be sticking.

3 The vacuum advance may be bad.

4 The hose to the vacuum advance may be plugged.

5 The fuel pump may have pressure but no flow (broken internally)

Timing check: Disconnect the vacuum advance and plug the line to the carb. At idle check the initial at about 8 degrees. At about 2500 rpm the timing should be 24 degrees (total of 32 with the initial) - you will need to mark the balancer for timing - tape can be used for a temporary solution - measure the circumference and divide it by 15 to get the 24 degree mark - tape/stamp the 24 degree marlk on the balancer. If the mechanical is fine, reconnect the vacuum advance. The idle timing should increase by about 14 degrees.

Fuel pump check: disconnect the fuel line at the carb and run a hose to a bottle. The pump should push 1 gallon per minute (half in 30 seconds).

 

[Mike McKown]

I'd be looking at the ignition system and wiring for your problem.

Flare fittings on fuel lines don't seal on the threads, they seal on the flare so the sealer will not do you any good. Sometimes you will get a poorly formed flare on either the line or the filter. Sometimes they can be seated if you tighten/loosen the assembly several times. Don't be timid about cranking down on the fittings if you have flare wrenches. The threads are pretty tough.

 

[cabbie]

OK, after much delay I've had a chance to work on this some more. It seems to be a problem with fuel delivery, I think. The problem crops up usually when I accelerate. Fuel does not squirt out of what I believe are the accelerator pump jets (correct me if I'm wrong, see circled portion of pic if you can - top center of carb area - two little jets)

After I let it idle for awhile, fuel will start squirting from these jets again. Any help on what the problem might be? Bad fuel pump? Some blockage in the carb itself? Floats not right? I still have to check the fuel pump output as recommended above, but the pressure seems OK when the jets do work. I'm getting ready to open the carb and check out the float and bowl, but want to get some opinions to make sure I'm looking in the right directions.

Thanks for all the help so far! This is so frustrating as I rarely get to drive it because problems are always cropping up....ahh the joys of owning a 42-year old car.....

 

[wishuwerehere82]

Yep,

Those are the accelerator pump outlets. If the floats are level and the bowls are full of gas, those should be squirting as soon as you crank up the engine. Since they don't, it could be a couple of things.
1) Your float bowls are still filling up so slowly so that the pump is not filled, or.
2) Your accelerator pump piston is not sealing to the walls of the cylindrical reservoir it sits in.
If you take the top screws off the carb. make sure you drive out the pivot pin on the accelerator pump lever arm, and dis-connect the choke lever by removing the screw on the end of the shaft first. Get a rebuild kit before you take it apart because you will need new gaskets.

 

[studiog]

Did it run decent before the rebuild? Sounds starved for fuel. The accelerator pump gets it fuel supply from the float bowls. The accelerator pump piston seal is leather and requires "flaring" and a coat of oil before install. The jets are in the bottom of the fuel bowl so you can't see how they are performing. All you can really see by looking down the carb is the accelerator pump orifices injecting fuel or the venturi "sucking" (actually creating low pressure) fuel into the manifold. Check your float level. Could be too low, (there are sight screws on the sides of the carb to check th level, or the needle valves are sticking or dirty or not properly rebuilt. At the bottom of the list would be the possibility you need larger jets but that is at the bottom of the list. If you need new jets it will be hard to find WCFB jets, but the Carter AFB jet kits are readily available, fit and work well.

 

[IH2LOSE]

Have you checked to see if the acelarator pump is operating ? if yes then with the air cleaner off and the car running cover the air horn with your hand trying to smother the carb while racing the motor.

What happens is by smothering the carb your creating a high vacum witch if the primaries are glogged you may pull the dirt thru and clear it out

 

[Ken Anderson]

I would bet on a bad fuel pump from what you've described.

 

[stepinwolf]

Well, I checked the heat riser and it is installed correctly. Fuel is squirting into the carb on acceleration, so that seems ok as well. I am in the process of changing the fuel filter, but am having some problems attaching the new filter. I can't get it to keep from leaking on either end. I've put some sealer on the threads, but it still seems to leak. Any tips on how to keep it from leaking? Any suggestions on the sealer I should use on the threads? I'm thinking the sealer I'm using may not be setting well enough.

Thanks for all the tips so far.

The carb was rebuilt by a recommended mechanic in upstate new york. He works on a lot of classic cars, and has done great work on mine. I've now moved the car to New Jersey so I am unable to take to him to check, and I haven't found a new mechanic in my area yet so I'm trying to see if I can get to the root of the problem myself.

Cabbie, my impression is that the problem was probably caused by the use of your thread sealer.

The worst thing I have heard so far in this thread, is the use of liquid thread sealer. :nono I cannot guarantee the starvation is directly related to it's use, but the exact same thing has actually happened to me in the past. After a carb rebuild, the threads were sealed on the various joints with a goo type sealer, and after only a relatively short period, the gasoline caused the excess sealer to deteriorate in the joints and come loose, thereby circulation through the fuel lines and the carb, in a way to cause partial blocking in the various fuel passages through out the carb.

As a result the engine bogged down during acceleration, and at times it even cause a type of backfire, when bursts of fuel passed through the various fuel passages. The fuel you can see squirting through the top of the carb, is not a guarantee that you will not have some limited starvation during acceleration. You would be surprised at the amount of fuel that is necessary to have smooth acceleration at start up.

The only sealer that you should used ( if it's absolutely necessary ) is the Teflon type of strip that you can use by wrapping a few turns around the male fittings.

In closing if my understanding regarding the type of sealer that was used is correct, my recommendations would be to once again have the carb pulled, and disassembled to check for the presence of foreign material in the assorted fuel passages. If you can't have it done by your previous mechanic, remove the carb it and send it out to one of the carburator rebuilders that regularly advertise in the NCRS " Driveline "

Stepinwolf

 

[Kid_Again]

Where in Joisey are you? I'm near Princeton and Ocean City and work due west of NYC. Send me mail.

 

[Ken Anderson]

No GM theaded fuel system was ever designed with sealers in mind. If you need a sealer, then there's a problem and stepinwolf is right-selers plug up carburetors.