question before I rebuild my carb - The 1947 - Present Chevrolet & GMC Truck Message Board Network

chevyman95 · 06-08-2011, 07:53 AM

I have a 454 in my truck with a holley double pumper carb. It sat for a while but I recently got it running but it accelerates horribly under throttle and if I even blip the throttle it will cut out. I am assuming this is because the carb has sat and got gummed up. Is there anything else that might cause this? Thanks

geezer#99 · 06-08-2011, 09:14 AM

Retarded timing also causes that. What distributor? What's your timing set at.?

**70STOVEBOLT** · 06-08-2011, 09:23 AM

Does it hesitate or just run rough under acceleration? Could possibly be the accelerator pump diaphragm. They will dry out and crack if they sit for a while with no fuel in the bowls. BTW, yours will have 2 of them if it's a double pumper.

chevyman95 · 06-13-2011, 09:55 AM

Quote:

Originally Posted by 70STOVEBOLT

Does it hesitate or just run rough under acceleration? Could possibly be the accelerator pump diaphragm. They will dry out and crack if they sit for a while with no fuel in the bowls. BTW, yours will have 2 of them if it's a double pumper.

It was this, I rebuilt the carb and the old accelerator pumps looked pretty bad. Runs like a champ now, Thanks for the advice

**70STOVEBOLT** · 06-13-2011, 12:45 PM

No problem, glad to hear you got it fixed.

06-08-2011, 07:53 AM	#1
chevyman95 Registered User Join Date: Mar 2010 Location: Underground Bunker Posts: 284	question before I rebuild my carb I have a 454 in my truck with a holley double pumper carb. It sat for a while but I recently got it running but it accelerates horribly under throttle and if I even blip the throttle it will cut out. I am assuming this is because the carb has sat and got gummed up. Is there anything else that might cause this? Thanks

06-08-2011, 09:14 AM	#2
geezer#99 Registered User Join Date: Aug 2009 Location: Bowser Posts: 13,738	Re: question before I rebuild my carb Retarded timing also causes that. What distributor? What's your timing set at.?

06-08-2011, 09:23 AM	#3
70STOVEBOLT Senior Member Join Date: Jun 2005 Location: Winona Lake, IN Posts: 6,424	Re: question before I rebuild my carb Does it hesitate or just run rough under acceleration? Could possibly be the accelerator pump diaphragm. They will dry out and crack if they sit for a while with no fuel in the bowls. BTW, yours will have 2 of them if it's a double pumper. __________________ 70 C/10 SWB 402/TH400/3.73 "The Needy Beast" 200,000 Mile Club Disc Brake Club Owner installed options: Front Sway Bar Power Steering Power Brakes Cigar Lighter Courtesy Lights Deluxe Side Markers Wiper Delay Sliding Rear Window Power Windows Power Locks Sniper EFI 2015 Silverado 1500 LS 4.3/6L80/3.23 lowered 2" front & rear

06-13-2011, 12:45 PM	#5
70STOVEBOLT Senior Member Join Date: Jun 2005 Location: Winona Lake, IN Posts: 6,424	Re: question before I rebuild my carb No problem, glad to hear you got it fixed. __________________ 70 C/10 SWB 402/TH400/3.73 "The Needy Beast" 200,000 Mile Club Disc Brake Club Owner installed options: Front Sway Bar Power Steering Power Brakes Cigar Lighter Courtesy Lights Deluxe Side Markers Wiper Delay Sliding Rear Window Power Windows Power Locks Sniper EFI 2015 Silverado 1500 LS 4.3/6L80/3.23 lowered 2" front & rear



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