73 mustang backfiring and saw a flame shoot out of carburator, what does this mean?

Question

The car starts up and idles farly uneasy, and when givien gas the carb kinda spits and at one point I saw flames shoot out. The car also runs like this crap.

Is this a mixture or timing issue or what? I just put in a new fuel pump, switched over from manual to electric but put a regulaor on.

Answer 1

Get dual points and it sounds like your points need to be adjusted use a match box side if you don't have a feeler gauge.I had a 73 Javelin and thats usually what caused this problem.

Answer 2

Ok, sounds like you are or maybe dealing with more than one problem here.

First: "IF" it is a holly carb, the moment it backfired through the carb it blew out the "Power Valve" (from memory on that thing). So you MUST replace that valve for it to run correct again (even if you fix the other problems). I used to keep 10 on hand just because of that. ANY backpressure in the manifold will blow those things.

Second: Backfiring through the carb is one of three problems.
1) Timing - check the timing with a light (and check the vacuum advance as well - it should be PORTED vacuum not constant), IF the timing is right then;
2) Bad Points - check your points (from mem that "should" be a points dist) make sure they have the right dwell / gap;
3) Burnt or Cracked Valve - if the timing is correct then it is possible you have a burnt or cracked valve. You can do a leakdown test to check that.

Also: After you replace the power valve, you need to reset the carb / and / you could have fouled plugs if you ran it too long with the power valve blown.
NOTE: be sure your regulator is set for NO MORE than 4LB's of pressure.

Answer 3

Low float level causing the Stang to lean out and burn your eyebrows off. Or the accelerator pump is not giving it the squirt of fuel it needs to spin up the motor when the throttle snaps open. Be very carefull Keep a damp towel to put out the fire or crank up the motor to pull the fire back in. Electric pump should have a safety switch out under the hood so you can shut down the fuelpump power if fire gets out of control. Electric pumps are very dangerious And car with added pump the continues to run after the engine stalls should also have a fire extinguisher in the car and garage to put out a fire.

Answer 4

Sounds like the timing is too hign causing it to backfire through the carburator. This might be caused by flooding also.

I recommend checking the timing, the point gap, IF it has points and the capacitor in the distributor. Good luck. Pops

Answer 5

It sounds like the timing is a little off, there is a slight possibility of a sticking valve but most likely the timing. Use a vacuum gages to set the timing if you don't have a timing light by setting the timing (move the distributor) until the vacuum is at its highest point . Good Luck and GOD Bless

Answer 6

if you recently installed new plugs and wires you may have gotten the firing order wrong when reinstalling correct firing order is stamped on front passenger side of intake.

also to agree with a classic such as this you cannot go wrong install ing a new electronic distributor most auto parts stores can get you one for around $200 to $500 depending on how deep your pockets are

more than likely it is a firing order problem

remember when diagnosing any problem start with the easiest and most obvious reason it is not always going to be a major malfunction so start with small inexpensive causes and work your way up to catastrophic and expensive

Answer 7

don't be too hasty, i'm making a wager the carbs have been dry for awhile, permit the motorcycle sit down for 3 or 4 days, the seals in carbs would swell up a sprint and there, undertaking solved, on a similar time as that is placing, why no longer verify the valve clearance

Answer 8

Timing could be off so is firing too early and backfiring through the intake valve or could have a burnt intake valve. Do a compression check to check valve. Also could be EGR valve problem. Does it have an air pump? if so could be athe anti backfire valve in this system.

Answer 9

turn the regulator down to 6 or 7 lbs. pressure and then make sure you don't have a plug wire crossed, if you don't have a fuel pressure gauge on it get one so you know where to set the fuel pressure.

Answer 10

Please don't tell me you are still running points. Upgrade to an electronic ignition. Check the timing and do the carburator checks others have mentioned.