shooting flame out the carb

[Boggin]

hey my 79 bronco shoots flame out the carb with the air filter off, does anyone know wat could be the problem? thanks

 

[adsm08]

Generally a timing issue. The cylinder contents are still burning when that intake valve opens, but since it's a wet intake the manifold contents ignite too.

It's basically a back-fire pointed the other direction.

Check your ignition timing, and if that is all hunkey-dorey it might just be time for a new chain.

 

[Boggin]

ok thanks, do i just check this with the light? and do you know what a 79 351M needs to be set at? i forgot to add thats what its for

 

[adsm08]

Yeah, pull the vac line off the dis modulator and then throw your light on it, warm. I'm not 100% sure of the advance for the 351M, but most Fords like to have it somewhere around 10*.

 

[Boggin]

yea i figured it was somewhere around there cause i can remember my brother doing his foxbody. what do you mean pull the vac line off the dis modular?
thanks

 

[adsm08]

Usually on those old carb'ed engines there will be a flying-saucer looking thing on the dis stem with a vacuum line going to it. You gotta take that line off and plug it to time it properly. Otherwise you are fighting the advance the whole time.

 

[Boggin]

ok thanks bud

 

[adsm08]

No problem. Glad to help when I can.

 

[xnickitynickx]

just in case you got any...it might be cool

 

[Boggin]

its only for a split second it happens. she dont catch on fire lol

 

[adsm08]

Yeah, it won't. It's a fairly self-extinguishing process, the burst of flame uses all the O2 in the intake and then suffocates and goes out.

Liquid fuel in the bowl won't burn too well either, its the fumes that burn.

 

[BlackBII]

You sure you have all the plug wires on correct?

If so, then yes, check your timing. The vacuum advance will look something like this, and it will be on the distributor. Unhook the vacuum line then set the timing.

 

[adsm08]

^ Yup, that's your timing advance vacuum modulator.

Not that we want to use big words here.

Good luck with it.

 

[straycat]

hey my 79 bronco shoots flame out the carb with the air filter off, does anyone know wat could be the problem? thanks

Darn, that is nothing to worry about!! My buddy Steve eats too much mexican food and shoots flame out his butt!!! lol


Straycat

 

[LearjetMinako]

Another thing to check besides timing is the order of spark plugs. Make sure the wires go to the correct spark plug.

One my buddies didn't do his right and we could not get it to run right (72' Caddy with 5xx cu in engine). He swore that he got the plug wires correct. I went on adjusting the carb mixture, doing my best. We both had our heads under the hood with the engine running. Gave a quick burst of throttle, BANG BANG, flames shot out of the carb. Could not quite hear for a few minutes. A week later, he found the problem, he had a few plug wires crossed.