Carburator problem?

[47heaven]

While driving last night I had the car cut out on me for a moment, then continued to run again for another hundred feet then cut out again. I pulled over and started the car up again, with a little hesitation, but as the engine was sputtering, I smelled raw gas and then it let out a tremendous backfire. After that, it started to run normal and I got it back into the garage.

Is this an adjustment issue or something a little more extreme?

[55 Fargo]

How about ignition/problem/component failure?

[47heaven]

How about ignition/problem/component failure?

That's what I thought, at first. I have a Stovebolt electronic ignition and just recently had the car tuned up. The problem is that it's a "come and go" thing, and when I take it in to be looked at, it runs fine...go figure.

[47heaven]

Wow, 54 hits on this, and no one, besides Rockwood, knows what the problem might be.

[aero3113]

Is your fuel pump original? Do you have any inline filters that can be clogging? When was the last time you opened up the carb and cleaned out the sediment? It sounds like one of the jets may be clogging and cutting off fuel supply for a moment. While you have the carb open I would check the float height also. Once the carb is all cleaned put it back together recheck the timing and go for a ride. I put a inline filter in to prevent any sediment getting to the carb.

[aero3113]

How about ignition/problem/component failure?

Fred may be right also,your coil may be going bad,condenser could be going bad also open the distributor and check the small jumper wire and make sure it is not grounding out somewhere in the distributor.

[Don Coatney]

Wow, 54 hits on this, and no one, besides Rockwood, knows what the problem might be.

Geez I am sorry for not responding right away:( I was busy working on some of my own issues that I have now resolved.

Electronic ignition systems normally work or they dont work. No in-between such as in non solid state contact point driven ingition systems. So I would rule out the ignition system as you were able to start the car and return to your garage.

Can you do a better job of describing this huge backfire? Did it pop through the carburetor, or through the exhaust? If your carburetor had a percoulation issue, and if raw gas entered your exhaust system, and if you have a slight exhaust system leak, the raw gas in your exhaust system could have ignited from the heat and caused a big boom.

I suspect you have a carburetor perculation issue. This is the same issue I just repaired on my flathead powered lawn mower. My repair was to lower the carburetor float level to allow more room for heat expansion of the gasolene in the float bowl. Suggest you do the same.

[47heaven]

Geez I am sorry for not responding right away:( I was busy working on some of my own issues that I have now resolved.

Electronic ignition systems normally work or they dont work. No in-between such as in non solid state contact point driven ingition systems. So I would rule out the ignition system as you were able to start the car and return to your garage.

Can you do a better job of describing this huge backfire? Did it pop through the carburetor, or through the exhaust? If your carburetor had a percoulation issue, and if raw gas entered your exhaust system, and if you have a slight exhaust system leak, the raw gas in your exhaust system could have ignited from the heat and caused a big boom.

I suspect you have a carburetor perculation issue. This is the same issue I just repaired on my flathead powered lawn mower. My repair was to lower the carburetor float level to allow more room for heat expansion of the gasolene in the float bowl. Suggest you do the same.

It's okay, Don...you are forgiven.

Your post has really made me think a lot about what I has been happening, and a lot of it makes sense. The backfife seemed to happen more towards the engine compartment as the engine seemed to be sputtering and I was giving it a little gas to keep it alive. I have noticed the smell of raw gas, especially when the engine is at about 180 and has been running a while. I mainly smell it after the car has been sitting for about 10 minutes, while I go in the store. When I go to start it, that's when I really smell the gas. I hold the gas pedle down and then turn the ignition. The car starts right up, but sputters a little, as if it's burning off extra gas. I have had this percolating issue before, but I thought the heat shield I had made would put a stop to it. What is causing the percolation?

Would using a carburator cleaner in the gas help or would it be better just to go through the whole carburator? It's only been on for about 2 years, and I don't know if the oil bath cleaner I put on there is doing it's job or not.

[greg g]

Heat is the cause of perculation (added to the fact that todays gas is more likely to expand at lowere temps). The perculation causes the fuel to expand and over flow the float bowl. the cure is to assure a good clean needle and seat seal and adjust the float properly or a bit lower than factory spec. However perculation is generally a hot start condition which actually floods the engine causing an over rich mixture that to wet to fire off.

How do your spark plugs look? What is the conditio of your fuel line from the tank to the pump? Is your fuel cap correct?

[Don Coatney]

My repair was to lower the carburetor float level to allow more room for heat expansion of the gasolene in the float bowl. Suggest you do the same.

[P-12 Tommy]

My repair was to lower the carburetor float level to allow more room for heat expansion of the gasolene in the float bowl. Suggest you do the same.

That's exactly what happened to mine awhile back. I lowered the float some and has been great since. Don hit the nail on the head with that one.

Tom