[DainBramaged]

OK, so I have been restoring a chevy pickup. I did a frame off, painted the frame, the whole 9 yards with a brand new 350 crate motor. We got the engine running and took the truck to the exhaust shop. It ran fine a number of times before the exhaust (custom 2.5" dual exhaust with high flow cat converters and flow masters exiting before the back wheels) as well as a couple of times after the exhaust. I started the truck earlier today and i heard what I think was a really faint back fire, then I heard it two or 3 more times, so I shut the truck off and popped the hood. When the hood popped smoke came bellowing out and there was a pretty good fire kicking behing the carb but in front of the distributor cap. It looked like little puddles of fuel were sitting on the intake (edlebrock performer). I put it out with my shirt and burt the tips of three of my fingers (it hurts to type this ;0). My question is, does anyone have any ideas how this could have started, and what can I do to prevent this in the future. I have spent about a year building this and it truly sucked to see it in flames! Thanks in advace!
Shawn

The attached picture is the most recent of the project that I have on the computer.

 

[garretthes]

Have you been smelling gas? I bet you have a fire extinguisher handy now
Welcome to the forum!

 

[DainBramaged]

My buddie that was helping with the project relocated the fire extenguisher, funny you should say that. No, there wasn't a gas smell and we didnt notice any fuel leaking before the incident...

 

[RCastle]

I had an Edelbrock carb on my 76 Camaro,rubber fuel line split and sprayed pressurized fuel on my distributor.See split in top photo.Burned the wiring harness and carb and dist.Towed it homeat 2:30 PM.By 10:00 PM that night me and my brother had it running.The pain was making new wiring for everything,took the longest.Had plenty of parts laying around to do all the repairs.Did go out and buy the correct metal line for Edelbrock carbs after that though.

 

[Centerline]

You obviously have a serious fuel leak somewhere around the carb. (This has nothing to do with your exhaust system by the way.)

A couple questions. Are you running an electric fuel pump? If so, are you running a pressure regulator? Also, have you checked the fuel line to the carb to see if it split?

Centerline

 

[DainBramaged]

Thanks for the replys... No, I am not using an electric fuel pump, its mechanical. I dont have a pressure regulator. The fuel lines going to the carb were held on by "clamps" that edelbrock sent with the carb, you squeeze it to get the clamp to open and let them go to have the clamp sqeeze the hose around the nipple. We replace the regular fuel hose with better fuel injection fuel hose (has more braiding within the rubber) and purchased some real clamps that can be tightened with a screw driver. We also replaced the wires that were burt by the fire and drove the truck around. No problems so far. I will keep you guys posted.

PS
I bought a fire ext and keep it in the truck now ;0)

 

[garretthes]

I have to agree with the above prognosis. The only thing that I don't understand is why the backfiring? Would a fuel line leak cause backfiring? We have a 2 part clue.
-Gas on the intake.
-Backfiring.
It could be a coincidence. Could the fuel leak cause the misfire?

 

[lluciano77]

Oh my god fire!

It sounds like the carb is flooded or leaking.

It is pretty common for an engine to backfire, and have the carb catch on fire. It is no big deal. Gas doesn't burn too hot. Usually the pool of gas on your intake will burn a mostly blue flame.

I have had a few fires last a couple minutes on my intake. I had rubber radiator hoses directly above the flames. The fires weren't even hot enough to damage the hoses.

 

[DainBramaged]

Well the fire did seem to burn pretty hot. Hot enough to burn through a couple of spark plug wires. The only thing I can think of is that the fire started before the backfire somehow, and the backfire was caused by a plug not firing because the wire had been tourched in half?

Just to add a little more detail, it was really cold outside (35 degrees) and I had just started the engine. It was idiling high because the electric choke was engaged. I tapped the gas to bring the idle down rather quickly without letting it warm up. Dont know if that would cause something?

 

[garretthes]

Did the fire damage your distributer?