Carb backfires and shoots flames?

[Blue71]

O.K. I am trying to get my '74 to run correctly. It takes forever to start. It starts and dies over and over 10-15 times before I can get it to finally idle. After it finally does idle for 30 sec. or so it'll die again 3 or 4 times. Then It'll finally idle steady. Once idling steady for a few minutes I can hit the throttle hard and it'll die. When it does.... It backfires thru the carb with either a puff of smoke, or a flame...it does this about 5-7 times. I have let it run for about 5 minutes. As I write this and just noticed that the idle went up a lot and is about 500-600 RPM's higher now and stays there. Any suggestions??? !!!!Update!!!!. I now went out and it revs up fine. No hesitation at all. I turned the idle down to about 800RPMs Sounds like a choke problem to me, but how do I fix it if it is. I can't wait for this thing to start for 15-20 minutes every time i drive her.

Any tips.


Thanks Much,

Blue71



Blue71

 

[Mr Joe]

My first thought is a timing issue. What's the ignition timing set at? When was the last time this engine ran? Could it have jumped time?

 

[rustbucket]

Check your timing and idle mixture. What did you do to the engine before this happened?

 

[BUCKETOBOLTS]

Do you have points or electronic ignition? If you have points, make sure they are adjusted and in good shape. When the engine spits back through the carb ussually it is either a timing issue or the mixture is very lean looking for fuel.

 

[wildbill]

%) %) %) How dose it run when you get it giong is it slow and dogie if so you mite have jumped on the timming. Fixed one nextdoor it did that had jumped. New gear and chain and good as new good luck. ;D ;D ;D Bill %)

 

[72_EB]

Blue,
Check the timing and report back. Sounds like classic timing issue to me too.
Maybe the holddown broke loose and timing is off.

 

[Blue71]

Hey Guys,

I drove the Bronco for about 30 min. after I got it to idle . The throttle response is good and no back fires. Only does it after setting for 8 hrs. or so or setting overnight. doesn't matter if it is cold weather or hot weather for some reason. The timing looks to be set at 10-11 deg BTDC. After it is warmed up a little and I drive it it has really good throttle response. I can cut it off and restart it and it fires right up with no lag on the starter at all. Like I said..only when I fire it up in the mornings or if it has sat a few hours. It was running pretty good a few weeks ago and then I did the (carb puke/roll down the hill backawards thing) and it seems like it has been harder to start since. IT really has alwaya acted similar to this on start-up, but it would only take 5-10 times to start it like it was cold and had to warm up. No backfiring or sputtering through the carb like it does now.

72....I checked the holddown and it is tight.

Bill, it goes when I hit the throttle..no sputtering.

Bucket..it has the points...changed them a few hundred miles ago..look good

Rust Bucket..I checked the mixture screws on the front of the carb. 2.5 turns out on both.

Joe, IT ran a few days ago. Still hard to start then as well. Timing is about 10-11 deg BTDC

Keep'em comin' guys.

Thanks Much,

Blue71

 

[broncnaz]

Check your advance mechanism in the dist both mechanical and vaccum make sure they are functioning properly sounds like the mechanical may be gummed up then loosens up when the engine is warm

 

[68ford]

try the ballist resistor bypass wire, mine sounded like your situation,just a thought and easy to check.

 

[Buckin74]

Blue-- Other than timming or distributor issues, I would lean toward checking the choke system. If it runs fine hot-- but not cold, check to see if the choke is working (don't know whether you have electric or mechanical choke).

 

[ken75ranger]

At this point I'd say choke also. Sounds like it's closing all the way and not opening partially once it's started. You gonna have to watch the carb while it's cold and see if it opens a little when you give it some gas.

 

[brian72]

At least get some pictures of the flames shooting out of the carb....that will be cool

 

[Bronco Ben]

one of those back fires could have taken out your power valve! Not sure but it sounds like a possibility to me.......good luck
Ben

 

[BUCKETOBOLTS]

I think it may be time to pull the carb and put a kit in it. That way you can check and set all the adjustment. Be sure to soak it in a good quality cleaner, too.

 

[airman]

I think we need to pin you down on electric or manual choke. Which one do you have and have you recently done something to it.

I had an electric choke that worked fine but when I went to the manual choke the mechanism hit the gasket and would stick.

When cold the choke plate should have a gap large enough to fit a car key into at least. If it closes more than that you will stall.

What carb are you running?

Jeff in AZ