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  Poor acceleration with Holley carb

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Author Topic:   Poor acceleration with Holley carb
Square Pants
Journeyman

Posts: 35
From: Phoenix, AZ
Registered: Aug 2002

posted 10-17-2002 09:50 PM     Click Here to See the Profile for Square Pants     Edit/Delete Message   Reply w/Quote
I bought a used street avenger 670 carb and have it on my car but I am getting poor acceleration with it. When cruising at low RPM, it has a flat spot before it takes off and if I floor it at an idle, it will always stumble and often times stall. When cruising at high RPM, there doesn't seem to be any problems at all.

The fuel bowl is adjusted to the bottom edge of the sight window and it idles fine. I have the primaries jetted one size below stock and have the heaviest vacuum secondary spring installed. Any ideas on what I can try out next?

Thanks

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-Lee
73 Convertible, 351C-2V, FMX, Weiand X-elerator, Holley 670 Street Avenger, Heddman Headers and 2.5" Flowmaster Dual Exhaust
And saving up for the next project...

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Moneymaker
Administrator

Posts: 14914
From: Lyons, IL, USA
Registered: May 99

posted 10-17-2002 10:11 PM     Click Here to See the Profile for Moneymaker   Click Here to Email Moneymaker     Edit/Delete Message   Reply w/Quote
Sounds like it's a bit short on accelerator pump shot Lee. Increase the squirter size 2-3 numbers.

------------------
Alex Denysenko
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Square Pants
Journeyman

Posts: 35
From: Phoenix, AZ
Registered: Aug 2002

posted 10-18-2002 12:12 PM     Click Here to See the Profile for Square Pants     Edit/Delete Message   Reply w/Quote
I changed all the way up to 35. Stock was 31, which was what it had. It seemed to help a little but I still am having a flat spot.

I did notice that the secondary fuel bowl looks like it's completely full. I also found the top of the sight plug broken off and sitting on my manifold. I just replaced both sight plugs a week ago too...

Looks like I'll be making a trip to the auto store to get another set of plugs to get that broken one replaced. Then I'll try to figure out why the secondary bowl is completely full with fuel.

Thanks.

------------------
-Lee
73 Convertible, 351C-2V, FMX, Weiand X-elerator, Holley 670 Street Avenger, Heddman Headers and 2.5" Flowmaster Dual Exhaust
And saving up for the next project...

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SteveLaRiviere
Administrator

Posts: 25777
From: Saco, Maine
Registered: May 99

posted 10-18-2002 07:49 PM     Click Here to See the Profile for SteveLaRiviere   Click Here to Email SteveLaRiviere     Edit/Delete Message   Reply w/Quote
Yes, set the rear float level before you even try anything else.

After that, check the setting of the front accelerator pump and see if someone adjusted it out of whack.

------------------
'70 Mustang Mach 1 - '72 Mustang Sprint - '94 F-150

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Square Pants
Journeyman

Posts: 35
From: Phoenix, AZ
Registered: Aug 2002

posted 10-19-2002 07:33 PM     Click Here to See the Profile for Square Pants     Edit/Delete Message   Reply w/Quote
Well I tore the carb apart today and found that the secondary float was bent so bad that it would never shut off. Also, as Steve suggested, I check the accerator pump and the previous owner did have it adjusted all out of whack.

After fixing these I made went with 1 size below stock for the primary jets and the secondary jets stayed that at stock size. I also went back to the 31 with the accelerator pump squirter. When I put it all back together, there was no flat spot!

And after a few test runs around the block to fine tune it, I think I have a permanent grin...

Thanks for all the good advice!

------------------
-Lee
73 Convertible, 351C-2V, FMX, Weiand X-elerator, Holley 670 Street Avenger, Heddman Headers and 2.5" Flowmaster Dual Exhaust
And saving up for the next project...

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