Backfire.... - The 1947 - Present Chevrolet & GMC Truck Message Board Network

chev74 · 11-18-2007, 02:27 PM

Is a backfire in the manifold a result of bad timing? too much fuel? not enough fuel?

Just put on a new edelbrock 1407... you can be cruising about 50mph still in the primaries, and give it enough gas that you should accelerate (not to the secondaries yet) but it backfires. If you ease into the secondaries it will accelerate fairly well, but not the way a 454 should if ya know what i mean.

WhaTS tHe PrOBleM?!?!

**slomotion** · 11-18-2007, 02:59 PM

Generally when they sneeze like that they're lean because the accelerator pump isn't putting a big enough shot of fuel in. Check your linkage and set it so you have a longer stroke. Another possibility is your float settings are too low not allowing enough fuel into the accelerator pump bore.

chev74 · 11-18-2007, 03:31 PM

how do I adjust these? I know there are 2 screws in the front for the air/fuel mixture, but which direction should i turn them? how much even?

How do i adjust the floats? the carb has always been a mystery to me, so i am trying to learn

cruiserman · 11-18-2007, 04:01 PM

Edelbrocks are very simple. The 2 screws are idle air/fuel mixture. Pop off the air horn to access the float.

Edelbrock 1407 manual Float instructions are on page 14.

beautimus · 11-18-2007, 06:04 PM

could you possibly have bent a push rod when you installed the manifold?

chev74 · 11-18-2007, 06:34 PM

didnt remove the manifold, so the answer is no. still the stock spread bore manifold

11-18-2007, 02:27 PM	#1
chev74 Addicted to Chevy Join Date: Dec 2004 Location: Tyler, Tx Posts: 857	Backfire.... Is a backfire in the manifold a result of bad timing? too much fuel? not enough fuel? Just put on a new edelbrock 1407... you can be cruising about 50mph still in the primaries, and give it enough gas that you should accelerate (not to the secondaries yet) but it backfires. If you ease into the secondaries it will accelerate fairly well, but not the way a 454 should if ya know what i mean. WhaTS tHe PrOBleM?!?!

11-18-2007, 02:59 PM	#2
slomotion Old Duffer Join Date: Mar 2003 Location: Maine Posts: 1,821	Re: Backfire.... Generally when they sneeze like that they're lean because the accelerator pump isn't putting a big enough shot of fuel in. Check your linkage and set it so you have a longer stroke. Another possibility is your float settings are too low not allowing enough fuel into the accelerator pump bore. __________________ '68 Short C20 Flatbed Dually w/ 292 4bbl, Langdon cast headers, and WC T5 trans. '81 G10 Shorty Van "Good judgement comes from experience, and a lot of that comes from bad judgement." Will Rogers "Under promise, then over achieve."

11-18-2007, 03:31 PM	#3
chev74 Addicted to Chevy Join Date: Dec 2004 Location: Tyler, Tx Posts: 857	Re: Backfire.... how do I adjust these? I know there are 2 screws in the front for the air/fuel mixture, but which direction should i turn them? how much even? How do i adjust the floats? the carb has always been a mystery to me, so i am trying to learn

11-18-2007, 04:01 PM	#4
cruiserman Registered User Join Date: Dec 2006 Location: Idaho Posts: 210	Re: Backfire.... Edelbrocks are very simple. The 2 screws are idle air/fuel mixture. Pop off the air horn to access the float. Edelbrock 1407 manual Float instructions are on page 14. __________________ 72 C2500 LWB 402 Sierra Grande 05 Odyssey 08 Tundra

11-18-2007, 06:04 PM	#5
beautimus Registered User Join Date: Mar 2002 Location: woodstock, alabama, usa Posts: 938	Re: Backfire.... could you possibly have bent a push rod when you installed the manifold? __________________ i survived cancer and kidney stones, but my kids are killing me.

11-18-2007, 06:34 PM	#6
chev74 Addicted to Chevy Join Date: Dec 2004 Location: Tyler, Tx Posts: 857	Re: Backfire.... didnt remove the manifold, so the answer is no. still the stock spread bore manifold



Register or Log In To remove these advertisements.

Register or Log In To remove these advertisements.