AVS rebuild issues

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markfh

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Location
Houston Texas
I rebuilt the AVS on my automatic 340 GTS and now it bogs when hitting the throttle. If I slowly press the throttle it will accelerate. Someone told me the new accelerator pump has neoprene that doesn't seal as good as the old leather with modern gas.

I still have the old one I took out. Any opinions on putting it back in or is there something else I'm missing here.
 
You cant use the old leather pump with the "new" gas. It wont last, dries out. MT
 
use a flapper of fine sandpaper on a dremel in the bore of the acc pump to hone the walls, the neoprene needs a smooth surface to seal to, not the as cast of the leather cups. Feel it and youll see what I mean Let us know, I got an AVS on the shelf thatll need a rebuild too.,
 
You sure you didn't lose a check ball for the pump? What makes you think it IS the pump? float levels?
 
With the engine OFF get a flashlight, remove the air cleaner and pump the throttle. Confirm that it has a good strong steady stream of fuel squirting into each primary barrel. If it does, it is not the pump. Also, make sure the pump rod from the throttle arm is connected into the hole closest to the carburetor on the pump rocker arm. That will give you the longest pump stroke. Lastly, make sure the "S" linkage connecting the pump rocker arm to the pump has the end of the "S" pointing to the driver's side. Installation the other way can cause binding.
 
I'm really not sure. The gold on mine is paint, factory would have been plated. This carb was a big dirty, oily mess before I rebuilt it 8 years ago. I just wanted to make it look nice.

Thanks, I get grief at car shows on my 66 charger duel quad setup, they don't agree on color of those parts. MT:burnout:
 
You sure you didn't lose a check ball for the pump? What makes you think it IS the pump? float levels?

I'm pretty sure but since I'm old I forgot. When I take it down again I'll check.
When I rebuilt it I followed the instructions and put everything including the floats to spec. But then again, I'm old.:D

What I get when the engine is off and I hit the throttle is a squirt on both sides. But, if I give a partial throttle then hit it full I get a dribble. That's what's causing the stumble which when the engine is cold will stall it out.

Thanks for all the help y'all givin me here. It's nice to get this dart back on the road even though it needs a little more tweaking.
 
With the engine OFF get a flashlight, remove the air cleaner and pump the throttle. Confirm that it has a good strong steady stream of fuel squirting into each primary barrel. If it does, it is not the pump. Also, make sure the pump rod from the throttle arm is connected into the hole closest to the carburetor on the pump rocker arm. That will give you the longest pump stroke. Lastly, make sure the "S" linkage connecting the pump rocker arm to the pump has the end of the "S" pointing to the driver's side. Installation the other way can cause binding.

Check, check, and check. After rebuilding I found I had a accelerator pump that was defective. Put it back on the car and it starts better, idles okay, but when I hit the throttle hard it still bogs. The video, short as it is, shows that I'm getting fuel in both venturi on the primary's but it bogs just when the fuel hits and would stall the engine if I don't let up on the throttle.

[ame="https://youtu.be/MW3Vns3TnDU"]https://youtu.be/MW3Vns3TnDU[/ame]
 
It's been years since I had one apart but I remember a valve down in a bore. Was stuck in mine. Carb cleaner didn't free it. I didn't know it was supposed to be free. Anyway next time apart my friend did and got valve free. Stumbled like you are talking about till he got valve free...
 
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