Carb Or Ignition Problems??

[Hal Copple]

I was thinking over my experience in my car. First, if you "run out of gas" at lots of throttle, or sustained heavy throttle, you might need a new fuel filter, or to check the tiny sintered bronze filters that some carbs leave in at the carb inlets. I have found on my car, that watching my fuel pressure gage, and feelling hesitation at heavy or sustained throttle was due to a partially full fuel filter. I even run a big Holley Canister filter, and still need to put in a new one from time to time. A new car might have picked up some junk just from the git-go.

another source of hesitation on heavy or sustained heavy throttle is that you are running your carb bowls dry, and raising the float level might help a lot. I don't think you want to do anything with your float level but just have it corrrect, not too high or too low, just right. I removed the bronze inlet filters on my Holley, by the way.

I had corrosion on the Horseshoe coil connector, but that simply gave me a momentary complete cut out, or a no spark at start, i put on a standard MSD coil, fixed that problem.

I think you can easily tell if you have a fuel delivery problem, because if your hesitation is not dependant on fuel consumption, it is not likely the former. I have had carb icing in other cars, but not yet in my present Holley car. But it does feel like you are running out of gas. I believe it is from humidity in the air, being superchilled by the fuel vaporization, not from gas in the fuel.

Which problem i had once in my TR-8, had water in my gas, due to a leak at the tank inlet, when the engine would get a slug of water, it would stumble and die. You can pump some gas into a container, and see if there is any water in it.

Some cars have had reductor problems in the distributor, too. If your runs fine but suddenly and immediatly hesitates and stumbles with sudden heavy cylinder pressures, IE, sudden full throttle, you might have a plug wire problem. I had this once years ago, the wire conneciton at the spark plug was not right, it was bent inside the connection, so under heavy immediate load, it would not pass spark, hence the hesitation. Sometimes it can be hard to be sure a plug wire is securely on the spark plug.

In short, if it is sustained heavy throttle, it is probably a fuel/carb problem, if it is truly intermittant and not related to throttle, it is most likely electrical, with the above, unless a bad plug wire, as above.

Let us know what turns up, so we can all learn more.

all the best,

[sparks]

First of all I must thank everyone for there quick in-put on helping me try to fix my car. After I mentioned to Eric at (perf. eng.) that when I opened my gas tank there was a tremendous amount of pressure release, AH HA he says. Gas cap not venting prop. He thinks this is prob. the problem. Unfortunately my sunny 55deg. days are now 15deg. w/snow on ground....So will have to wait to see. It usually(hopefully) is something simple. Thanks again guys. Oh yeh,Eric If you would like you can still send me out some plugs.......................SPARKS!