Weird fuel issue keeping me from driving my coupe. Any ideas?

[steve s]

Originally Posted by carbed87

not sure if i have that, but would that really be an issue if the fuel flows freely regardless of how the engine is running?

There are two reasons that a filter might be the problem. One is that it's plugged with crap that it was intended to catch. The other is that it is serving as a locus for a trapped bubble, which can slow or nearly stop the fuel flow. Although the latter would act (or look, if you could see it) like an "air lock", it is actually a bubble of fuel vapor. This is usually a problem for the summer time, but can happen any time, especially if you're using winter blend fuel on a non-wintry day. When I used that clear plastic in-line filter seen in my photo above (post #16), with the car idling in the driveway I could watch it fill up with fuel vapor until it shut down the engine.

[George Miller]

Originally Posted by Hook

I agree with George in post #9. Make sure it's not electrical by simply checking the spark next time it quits. I had a problem like yours, towing the A home twice. I kept changing parts in the distributor including putting in a complete new one with all new parts. Finally found a thread here on how to check the ignition system and found my switch was faulty and I had a problem with the shielded wire running from the switch. The main problem was with the switch that was causing a drop in voltage. If you find it's electrical, there are many threads on how to isolate the problem without throwing parts at it like I did!

Yes that is a common one on the Model A. Another is the junction box, with a crappy junction box from the past that shorts out on the fire wall. Also loose connections on the box, the switch, the amp meter. the modern lower plate can also be a problem.

[dansluck]

Are you sure it's fuel problem. Next time it happens place your hand on the coil. If it is hot let it cool and turn it upside down ( wires pointing up) and it should run. Buy a high quality coil if this your problem. GOOD LUCK

[stouchton]

Originally Posted by steve s

There are two reasons that a filter might be the problem. One is that it's plugged with crap that it was intended to catch. The other is that it is serving as a locus for a trapped bubble, which can slow or nearly stop the fuel flow. Although the latter would act (or look, if you could see it) like an "air lock", it is actually a bubble of fuel vapor. This is usually a problem for the summer time, but can happen any time, especially if you're using winter blend fuel on a non-wintry day. When I used that clear plastic in-line filter seen in my photo above (post #16), with the car idling in the driveway I could watch it fill up with fuel vapor until it shut down the engine.

Steve - I have been having an unexplainable fuel starvation issue, you may have just explained it. It definitely started when I added one of the filters that you described. Definitely removing the filter to see if the problem goes away. Thank you sir.

[Tom Wesenberg]

Where do you live, what was the outdoor temp when this happened, and what kind of gas are you using?
Today's gas boils much easier than the good gas of the 60's and 70's, and any ethanol in the gas makes it even worse.

Do as George said, and slowly pull the choke as soon as the trouble starts, to see if that helps at all. Then if it still dies, get out and hold the coil wire 1/4" from a head nut as you push the starter switch with the key on. These 2 quick easy checks should let you know if it's fuel or spark related.

[Will N]

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I had a similar experience. It'd just act like it ran out of gas and stall, always when restarting it while it was hot. Ran fine from a cold start. It was the float hanging up in the closed position alright, but I checked for burrs on the float shaft, binding on the shaft, sticking float valves, nothing.... Then I noticed a ridge on the inside of the float bowl casting. There was very little clearance between the end of the float opposite furthest from the hinge and the body of the bowl because of this ridge. When assembling and while everything was cold, the float would move freely. But when hot, the float would expand more than the cast iron, and it would hang up on this ridge. Dremel ground the ridge down- no more problems.

[Pilotdave]

Originally Posted by carbed87

I like your idea. Would you have a recommendation as to what coil? Additionally, do you think that this may be something that would cause the vehicle to not run?

Any good quality coil should do. I went to NAPA and asked for a coil with 3 ohms internal resistance for a tractor project - counter guy checked the catalog and offered me a couple of choices. That coil will likely last longer than I need the tractor!

My understanding is that a 4 cylinder engine will run with the wrong resistance coil, just not very well. I haven't tried it.

[Bruce Adams]

Not sure if this will fix your problem, but its real easy and MIGHT just cure it. Get your Harbor Freight tire pump with the pointy attachment, open the fuel line, and pump one stroke of air into the tank with the cap off and hopefully not too full. This back flush will blow away any debris and be good for a couple of thousand miles.

[Paul Bennett]

Bad coil

[pooch]

Hook a strobe light to coil wire and hang it where you can see it and go drive.

[aermotor]

I know this is very crude, but if it where MY car I would give it a pssst of brake cleaner in the carb, next time it quit and try to start - will know for sure if ignition or fuel issue. I know, may not be too smart.

John

[stouchton]

Here is how I approached it when my 31 did the same thing.

I removed the #1 plug strap from distributor, made sure it was good and tight on plug and positioned it about 3/16" for the contact on distributor and started her up. Had a nice spark that I could hear.

Let her idle till she quit - nice spark the whole time. Car would not restart immediately however I had my strong spark.

Next I pulled the cap off the bottom of carb. No gas drained out. So I new it was a fuel delivery issue.

Cracking the fitting at carb flow of fuel was strong.

I have changed needle/seat and floats and have no obvious interference. Made no difference. Also - this happened in the summer, but has not repeated in cold weather.

I do have the filter Steve mentioned above.... just thought it would be a good thing to have a better filter. Didn't really need it - guess I was just tinkering. May not have been a good thing to add!

[Pilotdave]

stouchton, did you check the fuel strainer in the carb for a blockage? Is the length of gas line on the carb side of the "wedding band" on the fuel line 1/8" or less?

[Big hammer]

Originally Posted by aermotor

I know this is very crude, but if it where MY car I would give it a pssst of brake cleaner in the carb, next time it quit and try to start - will know for sure if ignition or fuel issue. I know, may not be too smart.

John

Brake cleaner will make a gas that will KILL you! I hope you meant to say carb cleaner. Lucky for me I used brake cleaner on a lawn mower out side when I did the very stupid thing and used brake cleaning in the carb to get it running. I pushed it away from me and the fog ended up killing the grass and not me.

[rocket1]

I the sediment bowl won't fill up unless you take the fuel line off the carb it has to be a problem in the carb.

[BILL WILLIAMSON]

On Minerva, I found that with a "pencil" filter, a cast iron sediment bowl, 1/2 tank of gas, she would flow a 6" stream of gas at the bottom of the fuel line.
Bill W.

[DougT]

In small engine applications, there is a different filter for gravity feed systems than the ones with a fuel pump.

[stouchton]

Originally Posted by Pilotdave

stouchton, did you check the fuel strainer in the carb for a blockage? Is the length of gas line on the carb side of the "wedding band" on the fuel line 1/8" or less?

Yes to both. Absolutely no reason for fuel not to flow. And it only had issues when hot.

[jetrod]

an unvented gas filler cap will cause that symptom

[steve s]

Originally Posted by stouchton

Yes to both. Absolutely no reason for fuel not to flow. And it only had issues when hot.

It really sounds like vapor lock, which are almost fighting words for some folks.