AVS2 accelerator pump plunger too small

[Spadman]

My experience in rebuilding Carter AVS carbs in the 70’s and 80’s leads me to think the AVS2 plunger is too small. I took a new one with my engine to be dynoed and the operator said the accelerator pump didn’t work and he didn’t use it. I opened it up today and found a 5/8” plunger in a 7/8” hole. Called Edelbrock and after an hour waiting the tech said that’s how it was supposed to be. I remember a sliding fit back in the day. What’s your experience?

 

[RustyRatRod]

If the sides of the plunger don't contact and seal with the I.D. Of the pump bore, the pump simply will not work.

 

[Spadman]

If the sides of the plunger don't contact and seal with the I.D. Of the pump bore, the pump simply will not work.

I don’t see any way it could work otherwise. I tried but couldn’t convince the tech. He said I could buy another plunger if I liked and gave me the part number. I’m not at all happy. I’m wondering if they really are all that way. Poor product if they are. He suggested a sticking ball valve.

 

[RustyRatRod]

Here you go bud. I don't know what the Edelbrock guy is smokin.

Pump

 

[Spadman]

Here you go bud. I don't know what the Edelbrock guy is smokin.

Pump

Thank you so much. I feel like fighting them but, … life is short.

 

[Bewy]

I think you will find the Edel pump plunger is 13/16". Same as the TQ & some later Carter AVS carbs.

 

[Spadman]

I think you will find the Edel pump plunger is 13/16". Same as the TQ & some later Carter AVS carbs.

That is reasonable. It would leave 1/32 clearance in a 7/8 hole. I ordered a 13/16 one from the store Rusty suggested. The one that came in my new AVS2 is simply too small. I didn’t mic it, but it’s not even close to the size of the well. I’ll report the fit when I get it.

 

[Spadman]

Some conclusions: 1) I didn’t notice that the pump well is tapered top to bottom so a plunger will be tighter by the time it is in the pumping position. No matter, the one supplied on the new Edelbrock AVS2 still doesn’t work. 2) As Bewy said the nominal size is 13/16, and I checked a 1969 Carter AVS which is the same. 3) The one I got from Quadrajetparts per RRR’s suggestion works fine. I checked the Edelbrock one again after sitting in fuel for a bit as suggested by their Tech. It will never work. It’s junk.