Edelbrock carb accelerator tuning question - The 1947 - Present Chevrolet & GMC Truck Message Board Network

J Williams · 07-01-2014, 11:46 AM

Okay, I know the comments are going to be get a Holley or Demon but I do not have the cash right now. My question is the accelerator pump is not fast enough. I have adjusted the linkage to the top hole and it made a big difference but not big enough. Is there anything else I can do to make the throttle response faster? The 650 cfm is on a performer series high rise intake atop a 350 with a half rad cam and 10-1 flat top pistons. Not a hot rod but it does need fuel, when I hit the throttle fast you can hear the large volume of air along with that hated stall before the fuel catches up. Any tips would be very helpful. Thanks

**PGSigns** · 07-01-2014, 01:37 PM

Sounds like the air valve in the back may be a little off. Have you worked on adjusting it?
Jimmy

J Williams · 07-01-2014, 01:57 PM

Are you talking about the secondary air flap. If so I have not played with it. Can you give me some tips on this adjustment. From what I have read after you loosen it you adjust it to closed and then 1 and 1/2 turns is what the factory setup is. What would be your suggestion?

morethanstock66 · 07-01-2014, 02:42 PM

You can get higher performance accel pumps for the carb.

http://www.summitracing.com/search?S...lerator%20pump

Wrenchbender Ret · 07-01-2014, 04:52 PM

You may need smaller metering rods or larger jets. Often These carbs have to be tailered to the engine. Look down the throat with the engine off & work the throttle. The accae. pump should put out 2 solid squerts. The pumps are usually leather. Sometimes you have to take it out & soak it in oil & massage it a little. They dry out. When you have the top off its a good time to check the float level If it is too low it will cause this problem.
The secondary air valves are not adjustable on this carb unless you have the AVS style.

geezer#99 · 07-01-2014, 04:56 PM

The stall isn't caused by lack of fuel.
It's caused by lack of timing.
What's your initial timing set at?

cadillac_al · 07-01-2014, 09:02 PM

You can download the owners manual for that carb online. It's pretty helpful.

donut · 07-01-2014, 09:13 PM

Quote:

Originally Posted by geezer#99

The stall isn't caused by lack of fuel.
It's caused by lack of timing.
What's your initial timing set at?

My first thought when I read it.

geezer#99 · 07-01-2014, 09:30 PM

Quote:

Originally Posted by donut

My first thought when I read it.

Yup!!
Everybody forgets the rule!!
Timing first, carb second!!

crazy longhorn · 07-02-2014, 01:50 AM

Amen brothers....I will 3rd that "timing 1st, then set the carb"....Longhorn

J Williams · 07-07-2014, 12:46 PM

Well my timing is set at 10 so I think this should be good. I have played with the timing both directions and it just seems to get worse. I attempted to fix the timing first, I guess I should have mentioned that in the beginning. Thanks for the info though I always appreciate any help I can get.

geezer#99 · 07-07-2014, 03:32 PM

At your elevation you can run way more timing. Bump it up until it pings or is hard to start.
Also due to elevation you need to lower your float level a bit. Try an 1/8 to start.

J Williams · 07-08-2014, 11:35 AM

Thanks I will give it a try

07-01-2014, 11:46 AM	#1
J Williams Registered User Join Date: Jun 2014 Location: Paul idaho Posts: 263	Edelbrock carb accelerator tuning question Okay, I know the comments are going to be get a Holley or Demon but I do not have the cash right now. My question is the accelerator pump is not fast enough. I have adjusted the linkage to the top hole and it made a big difference but not big enough. Is there anything else I can do to make the throttle response faster? The 650 cfm is on a performer series high rise intake atop a 350 with a half rad cam and 10-1 flat top pistons. Not a hot rod but it does need fuel, when I hit the throttle fast you can hear the large volume of air along with that hated stall before the fuel catches up. Any tips would be very helpful. Thanks __________________ 63 C10

07-01-2014, 01:37 PM	#2
PGSigns Senior Member Join Date: Jan 2011 Location: Hayes Va Posts: 4,569	Re: Edelbrock carb accelerator tuning question Sounds like the air valve in the back may be a little off. Have you worked on adjusting it? Jimmy __________________ 60 to 66 Chevy and GMC window decals http://67-72chevytrucks.com/vboard/s...d.php?t=661131 Good friends, good food and a hotrod what else do you need? 1966 BBW long fleet Daily driver 1965 BBW short fleet Sold and going to a good home 1965 Suburban 2003 3500 Duramax 2005 Ultra Classic

07-01-2014, 01:57 PM	#3
J Williams Registered User Join Date: Jun 2014 Location: Paul idaho Posts: 263	Re: Edelbrock carb accelerator tuning question Are you talking about the secondary air flap. If so I have not played with it. Can you give me some tips on this adjustment. From what I have read after you loosen it you adjust it to closed and then 1 and 1/2 turns is what the factory setup is. What would be your suggestion? __________________ 63 C10

07-01-2014, 02:42 PM	#4
morethanstock66 Registered User Join Date: Mar 2014 Location: College Station, TX Posts: 213	Re: Edelbrock carb accelerator tuning question You can get higher performance accel pumps for the carb. http://www.summitracing.com/search?S...lerator%20pump __________________ 63 SWB Stepside --Current Project http://67-72chevytrucks.com/vboard/s...d.php?t=836390 66 SWB Fleetside (Stacy) 350ci/Th400 --Gone http://67-72chevytrucks.com/vboard/s...45#post6595745 67 LWB Fleetside (Annabel)350ci/SM420. 7 Year Restoration --R.I.P. http://67-72chevytrucks.com/vboard/s...d.php?t=633867

07-01-2014, 04:52 PM	#5
Wrenchbender Ret Registered User Join Date: Oct 2005 Location: Overland Park, Ks. Posts: 5,229	Re: Edelbrock carb accelerator tuning question You may need smaller metering rods or larger jets. Often These carbs have to be tailered to the engine. Look down the throat with the engine off & work the throttle. The accae. pump should put out 2 solid squerts. The pumps are usually leather. Sometimes you have to take it out & soak it in oil & massage it a little. They dry out. When you have the top off its a good time to check the float level If it is too low it will cause this problem. The secondary air valves are not adjustable on this carb unless you have the AVS style.

07-01-2014, 04:56 PM	#6
geezer#99 Registered User Join Date: Aug 2009 Location: Bowser Posts: 13,731	Re: Edelbrock carb accelerator tuning question The stall isn't caused by lack of fuel. It's caused by lack of timing. What's your initial timing set at?

07-01-2014, 09:02 PM	#7
cadillac_al Registered User Join Date: Oct 2013 Location: Maine Posts: 2,375	Re: Edelbrock carb accelerator tuning question You can download the owners manual for that carb online. It's pretty helpful. __________________ 76 Chevy K20 76 GMC K15 77 Chevy C10 77 Chevy K10

07-02-2014, 01:50 AM	#10
crazy longhorn Fabricate till you "puke" Join Date: Jun 2002 Location: Ill Posts: 9,402	Re: Edelbrock carb accelerator tuning question Amen brothers....I will 3rd that "timing 1st, then set the carb"....Longhorn __________________ 69 longhorn,4" chop,3/5 drop, 1/2 ton suspension/disc brakes,1 1/2" body drop,steel tilt clip, 5.3/Edelbrock rpm intake/600 carb, Hooker streetrod shorties,2 1/2" exhaust/ H pipe/50's Flows , 6 spd Richmond trans,12 bolt/ 3.40 gears....

07-07-2014, 12:46 PM	#11
J Williams Registered User Join Date: Jun 2014 Location: Paul idaho Posts: 263	Re: Edelbrock carb accelerator tuning question Well my timing is set at 10 so I think this should be good. I have played with the timing both directions and it just seems to get worse. I attempted to fix the timing first, I guess I should have mentioned that in the beginning. Thanks for the info though I always appreciate any help I can get. __________________ 63 C10

07-07-2014, 03:32 PM	#12
geezer#99 Registered User Join Date: Aug 2009 Location: Bowser Posts: 13,731	Re: Edelbrock carb accelerator tuning question At your elevation you can run way more timing. Bump it up until it pings or is hard to start. Also due to elevation you need to lower your float level a bit. Try an 1/8 to start.

07-08-2014, 11:35 AM	#13
J Williams Registered User Join Date: Jun 2014 Location: Paul idaho Posts: 263	Re: Edelbrock carb accelerator tuning question Thanks I will give it a try __________________ 63 C10

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