Carb rebuild kit?
- Thread starter MikeM_66_Stang
- Start date
Nice thing about the log is there are very few places to leak. Carb base, adaper/heater plate and then any accessory or emissions hoses. The classic way to check is spray carb cleaner around those areas with engine running. If the idle changes at all you found the leak. There should not be anything other than down the carb throat that should cause a change.
I think you need to beg borrow or steal a dwell/tach meter and it sounds like a hand vac pump/gauge will be handy also.
Wrong dwell could cause your problem
Issue with the advance could also easily cause the problem especially since you likely have a load o mattic that does not have the weights and springs you also may have an issue with the SCV in the carb.
I think you need to beg borrow or steal a dwell/tach meter and it sounds like a hand vac pump/gauge will be handy also.
Wrong dwell could cause your problem
Issue with the advance could also easily cause the problem especially since you likely have a load o mattic that does not have the weights and springs you also may have an issue with the SCV in the carb.
Change the PCV Valve. May not help, but won't hurt. PCV Valves are "controlled" vacuum leaks.
Have you confirmed the accelerator pump is working?
How quick does it start cold? Describe to us a cold start, like how much cranking, how many pumps on the gas, ect...
How quick does it start cold? Describe to us a cold start, like how much cranking, how many pumps on the gas, ect...
MikeM_66_Stang
New member
OK - answers to your questions:
1. The carb does not have an accelerator pump. It has only the main pump. (In other words, it looks like the one in your picture except there is no pump on the passenger side, only the driver side.) I replaced the pump diaphragm (and the power valve also) during the rebuild.
2. A cold start when the car has been sitting for several hours requires one firm press of the gas pedal to the floor, then one pedal pump while cranking, and it fires right up. When starting from cold, it will run at idle for about a minute, smooth at first, then gettting rougher and rougher until it dies. Once it's warm, it will start right up, but idle is very rough and it dies in about 10 sec. Engine runs fine as long as I give it some gas.
3. I replaced the PCV valve last night - no change.
4. I'm not sure how we would use a vacuum gauge since I can't get the engine to run long enough to use it - however my friend has one and he is bringing it over tonight - any suggestions? I can try the carb cleaner trick also, but since I can't get it to run at idle, I'm not sure if this will work either.
5. Timing - I really don't think it is timing, because we cannot hear any misfiring, missing, or other strange sounds when the throttle is opened up. I would think that a timing problem severe enough to cause engine stall would be more audible. Also keep in mid that this problem happened suddenly one day; the engine ran fine before that.
Tonight we are going to try running the engine from a standalone gas can (directly into the fuel pump) to rule out any fuel contamination issues.
I also saw in another thread on here today that someone else rebuilt an Autolite with the Napa kit, and had to adjust the float about 3/16". Now they have the same problem I do. He thought the spec in the kit's instructions might be wrong, and the bowl is now filling too much. So I'll try moving the float down about 3/16" tonight.
If none of that works, well, I borrowed a timing light yesterday, I'll try checking timing. Any other thoughts?
EDIT: By the way, have I told you guys thanks for all the help and patience with stupid questions, y'all are the BEST!!
1. The carb does not have an accelerator pump. It has only the main pump. (In other words, it looks like the one in your picture except there is no pump on the passenger side, only the driver side.) I replaced the pump diaphragm (and the power valve also) during the rebuild.
2. A cold start when the car has been sitting for several hours requires one firm press of the gas pedal to the floor, then one pedal pump while cranking, and it fires right up. When starting from cold, it will run at idle for about a minute, smooth at first, then gettting rougher and rougher until it dies. Once it's warm, it will start right up, but idle is very rough and it dies in about 10 sec. Engine runs fine as long as I give it some gas.
3. I replaced the PCV valve last night - no change.
4. I'm not sure how we would use a vacuum gauge since I can't get the engine to run long enough to use it - however my friend has one and he is bringing it over tonight - any suggestions? I can try the carb cleaner trick also, but since I can't get it to run at idle, I'm not sure if this will work either.
5. Timing - I really don't think it is timing, because we cannot hear any misfiring, missing, or other strange sounds when the throttle is opened up. I would think that a timing problem severe enough to cause engine stall would be more audible. Also keep in mid that this problem happened suddenly one day; the engine ran fine before that.
Tonight we are going to try running the engine from a standalone gas can (directly into the fuel pump) to rule out any fuel contamination issues.
I also saw in another thread on here today that someone else rebuilt an Autolite with the Napa kit, and had to adjust the float about 3/16". Now they have the same problem I do. He thought the spec in the kit's instructions might be wrong, and the bowl is now filling too much. So I'll try moving the float down about 3/16" tonight.
If none of that works, well, I borrowed a timing light yesterday, I'll try checking timing. Any other thoughts?
EDIT: By the way, have I told you guys thanks for all the help and patience with stupid questions, y'all are the BEST!!
You sure your choke is pulling off? That cold start sounds like it. Like it works right until it gets warm and then drifts closed and/or stays closed.
Make sure the choke spring is engaged in the black cap. Just as a test, pull the black cap off the choke pulloff and operate the choke by hand to reproduce proper function. Meaning: pull the choke all the way off after a minute of warm up and see if it still runs badly. If no, that is the problem. If yes, you are not out any money.
Make sure the choke spring is engaged in the black cap. Just as a test, pull the black cap off the choke pulloff and operate the choke by hand to reproduce proper function. Meaning: pull the choke all the way off after a minute of warm up and see if it still runs badly. If no, that is the problem. If yes, you are not out any money.
I very much doubt you have no accel pump. On the 1100s, the auto carbs have two very similar "pumps." In reality, one is a Pump, and the other a Dashpot. The manual carbs have no Dashpot.
Try unscrewing the idle mixture screw all the way out, and spray carb cleaner into the hole. Use the little tube so you get as much force into the stream as possible.
There's a pivoting "Cam" that flops around when the Choke is "Open," but gets place under the High Speed Idle Screw when the Choke Closes. The reason you need to step down on the gas pedal when starting, is so the cam is free to move up under the screw to set the Fast Idle. The Fast Idle is set by manually rotating the cam to the 2nd step under the High Speed Idle Screw.
If you're overfilling your bowl, it might account for the ability to start cold, even if the choke is too "Lean." In troubleshooting, if you disturbed nothing else (like timing), then the problem usually lies with the item you replaced/repaired. You have nothing to lose by dropping the float 3/16s or so, and trying it out.
Try unscrewing the idle mixture screw all the way out, and spray carb cleaner into the hole. Use the little tube so you get as much force into the stream as possible.
There's a pivoting "Cam" that flops around when the Choke is "Open," but gets place under the High Speed Idle Screw when the Choke Closes. The reason you need to step down on the gas pedal when starting, is so the cam is free to move up under the screw to set the Fast Idle. The Fast Idle is set by manually rotating the cam to the 2nd step under the High Speed Idle Screw.
If you're overfilling your bowl, it might account for the ability to start cold, even if the choke is too "Lean." In troubleshooting, if you disturbed nothing else (like timing), then the problem usually lies with the item you replaced/repaired. You have nothing to lose by dropping the float 3/16s or so, and trying it out.
