Carb'd Chevy 350 Question - Carb backfire

FJ40_owner · 03-17-08, 04:39 PM

My 40 has a 78 350 installed. I run a Rochester 2 barrel carb. There is no smog stuff on it. Recently when running at moderate rpm, say 2000, engine is warm, when I put my foot into it the engine will sneeze through the carb.

My stock 40 used to do this and the solution was a new gasket around the accelerator pump, as I recall.

The only PM I have done is fluid changes, air filter and plugs. The PM was done months ago.

I run regular CA fuel.

Should I check the timing or might something be wrong with the carb?
The choke is OK and not stuck closed.

Thanks,

BigJim

Gumby · 03-17-08, 06:20 PM

Accelerator pump sounds like the culprit.

baxter650 · 03-17-08, 11:20 PM

Engine off, look down the carb throat, move throttle to w/o, look for pump shot.

Gumby · 03-18-08, 06:38 AM

definitely with the engine off. You'll look goofy without eyebrows.

NeverSummer · 05-12-08, 12:21 AM

Quote:

Originally Posted by Gumby

definitely with the engine off. You'll look goofy without eyebrows.

LMAO! I have seen this happen!

Chevinater77 · 06-04-08, 07:06 AM

my 72 chevy 2 wheel drive long bed with a 350 with a 2 barrel carb does this with bad gas. We just picked the rig up so i plan to get a carb "rebuild" kit. and do the gaskets and new filters for it! Mine only did it around 50-60 MPH. and only when in drive. when i ran premium it stopped doing it so much but still did a little!

03-17-08, 04:39 PM	#1
FJ40_owner IH8MUD Addict Join Date: Aug 2005 Location: El Dorado County CA TLCA# 16294 Posts: 546	Carb'd Chevy 350 Question - Carb backfire My 40 has a 78 350 installed. I run a Rochester 2 barrel carb. There is no smog stuff on it. Recently when running at moderate rpm, say 2000, engine is warm, when I put my foot into it the engine will sneeze through the carb. My stock 40 used to do this and the solution was a new gasket around the accelerator pump, as I recall. The only PM I have done is fluid changes, air filter and plugs. The PM was done months ago. I run regular CA fuel. Should I check the timing or might something be wrong with the carb? The choke is OK and not stuck closed. Thanks, BigJim __________________ Third generation Californian! If you don't like it here, leave. And take your fat wife and screeming kids with you.

03-17-08, 06:20 PM	#2
Gumby Former Wheeler Join Date: Dec 2002 Location: Knee deep in hookers and gin TLCA# 5658 Posts: 4,968	Accelerator pump sounds like the culprit. __________________ War Pig and Cerdito "Don't you know, Stan, it's *always* between a Giant Douche and a Turd Sandwich."

03-17-08, 11:20 PM	#3
baxter650 IH8MUD Regular Join Date: Aug 2005 Location: Abbotsford B.C. Posts: 430	Engine off, look down the carb throat, move throttle to w/o, look for pump shot. __________________ 1980 PU 9" lift 383 38" Swampers 1993 FZJ80 6" slee lift 37s 2000 XR671L 83 BJ60 under construction 2008 XR650L

03-18-08, 06:38 AM	#4
Gumby Former Wheeler Join Date: Dec 2002 Location: Knee deep in hookers and gin TLCA# 5658 Posts: 4,968	definitely with the engine off. You'll look goofy without eyebrows. __________________ War Pig and Cerdito "Don't you know, Stan, it's *always* between a Giant Douche and a Turd Sandwich."

06-04-08, 07:06 AM	#6
Chevinater77 IH8MUD Regular Join Date: Feb 2007 Location: Wenatchee, Washington Posts: 230	my 72 chevy 2 wheel drive long bed with a 350 with a 2 barrel carb does this with bad gas. We just picked the rig up so i plan to get a carb "rebuild" kit. and do the gaskets and new filters for it! Mine only did it around 50-60 MPH. and only when in drive. when i ran premium it stopped doing it so much but still did a little! __________________ Its not a Passion, its an Obsession Cruiser~95 stock 80 series, Goodyear Forterra Triple-Treds, Samco sport PHH. Princess Ride~2008 Toyota Tundra Crewmax limited Chevinater~ 77 Chevy 3/4 ton 350/350/203 with 44 front 14ff rear, 4.56s, 6 inchs 35x12.5x16.5 bfg m/t

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