Gary,
I watched you video again and I have some questions and comments.
I know you have been talking about adjusting fuel bowl levels, but I'd like to confirm something:
I believe you stated that the stumble happens just as you mash the throttle down. After you mash the throttle down, it stumbles a bit, then seems to recover after a second or so.
If the above is correct then I would not suspect the floats or float bowls. If your float bowls were low and you were eventually starving the car of fuel, this would happen at full throttle after a few seconds of full throttle. I do not believe it would happen immediately when you step hard on the throttle. If you had a fuel starvation issue at that point, you would have it for partial throttle situations as well.
Now mind you, I am not an expert carb tuner. But, at idle, your carb is using an idle circuit. These are often little slots or holes just below the throttle plates in the carb that dribble fuel into the engine while it is idling. When you slam open the throttle to accelerate, you transition off of this idle circuit to your venturis. As you mash the throttle, the accelerator pump squirts raw fuel into the engine to help with this transition. So my first suspicion would be your accelerator pump adjustment.
Again, assuming text in blue above is correct, I would try this simply check:
1) Have the car off, ideally after it has run for a minute or more - this is just to be sure fuel has not evaporated out of the carb after the car has been sitting. It does not necessarily need to be warmed up.
2) Remove the air cleaner
3) Look into the primary venturis of your carb - hold the choke door open if you need to.
4) Just BARELY start pulling the throttle back. You should immediately see some fuel drip out of the accelerator pump. I'll say this again because it is important: This should happen with the most MINUTE throttle action. Try this several times to get the hang of it. The tiniest bit of throttle travel should cause some fuel to come out of the accelerator pump in the throat of the carb.
This is an easy test as obviously no tear down is needed. If you have a delay before the accelerator pump provides raw fuel, this could cause the stumble. (Of course, it could be other tuning things, but this is an easy test to verify proper operation of the accelerator pump circuit.)
Let us know what you find!
Hawk
I watched you video again and I have some questions and comments.
I know you have been talking about adjusting fuel bowl levels, but I'd like to confirm something:
I believe you stated that the stumble happens just as you mash the throttle down. After you mash the throttle down, it stumbles a bit, then seems to recover after a second or so.
If the above is correct then I would not suspect the floats or float bowls. If your float bowls were low and you were eventually starving the car of fuel, this would happen at full throttle after a few seconds of full throttle. I do not believe it would happen immediately when you step hard on the throttle. If you had a fuel starvation issue at that point, you would have it for partial throttle situations as well.
Now mind you, I am not an expert carb tuner. But, at idle, your carb is using an idle circuit. These are often little slots or holes just below the throttle plates in the carb that dribble fuel into the engine while it is idling. When you slam open the throttle to accelerate, you transition off of this idle circuit to your venturis. As you mash the throttle, the accelerator pump squirts raw fuel into the engine to help with this transition. So my first suspicion would be your accelerator pump adjustment.
Again, assuming text in blue above is correct, I would try this simply check:
1) Have the car off, ideally after it has run for a minute or more - this is just to be sure fuel has not evaporated out of the carb after the car has been sitting. It does not necessarily need to be warmed up.
2) Remove the air cleaner
3) Look into the primary venturis of your carb - hold the choke door open if you need to.
4) Just BARELY start pulling the throttle back. You should immediately see some fuel drip out of the accelerator pump. I'll say this again because it is important: This should happen with the most MINUTE throttle action. Try this several times to get the hang of it. The tiniest bit of throttle travel should cause some fuel to come out of the accelerator pump in the throat of the carb.
This is an easy test as obviously no tear down is needed. If you have a delay before the accelerator pump provides raw fuel, this could cause the stumble. (Of course, it could be other tuning things, but this is an easy test to verify proper operation of the accelerator pump circuit.)
Let us know what you find!
Hawk
