Stumped

[Lenny Bruce]

Ok fellas here’s one that’s got me crazy!! Our ‘30 coupe starts right up and idles great. I take it up the road and within a minute it seems I totally lose power for a second enough for it to stall out and backfire! I replaced all the components in the distributor. All wires to the key switch and distributor are fine. Ground wire is
Good. The wires in the junction box are all good. Maybe it’s not electrical? Sure acts it…. Any ideas would be greatly appreciated!

[ronn]

sticky valve? how long has it been sitting?

[Lenny Bruce]

It’s been driven a handful of times this summer with no issues

[Lenny Bruce]

The wife was driving it this spring and it died on her. Thought it was running out of gas but fired right back up. Now it starts up and drives off with no issues but eventually sooner then later it acts up

[nkaminar]

There is a partial clog in the gasoline supply. It could be anywhere from the tank to the carburetor. Start by taking off the line at the carburetor and check flow there. Do this outdoors and with a fire extinguisher handy. If flow is good your clog is in the carburetor. You may have to drain the tank and take the valve at the bottom out. Look in the tank with a flashlight.

[Oldbluoval]

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I’d think fuel too. If that’s all clear check coil.

[Gary/IA]

Originally Posted by Lenny Bruce

The wife was driving it this spring and it died on her. Thought it was running out of gas but fired right back up. Now it starts up and drives off with no issues but eventually sooner then later it acts up

I had several instances such as this happen also. It would always start back up and run fine for many miles. After replacing one item at a time to locate problem, finally discovered that there were tiny flakes of something between the inner and outer layer of the gas cap that would move and eventually block air flow. Never suspected the gas cap as car would run fine for hundreds of miles before suddenly dying and then immediately restarting to run fine for many more miles.

[Jim/GA]

^^^
THIS!

Gas Cap!

Easy to test: take the cap off and drive around. Some people just loosen the cap, but to be certain, remove it to test.

This happened to my friend just 3 days ago with his '31 pickup. I removed the gas cap and the truck ran great.

[Bob from Northport]

Gas cap or the filter in the tank

[mcgarrett]

Your problem is fuel flow...or a lack thereof.

I had the same problem with a '31 Slant Windshield Sedan I owned previously. Turns out I had so much rust in the bottom of the tank it would slosh around while driving and stop up the fuel shutoff valve. Had to remove the fuel shutoff valve and clear the line with a piece of heavy wire to get fuel flowing again. After a lot of effort, I removed 1 POUND of rusty scale from the bottom of the tank. Once I did that, no more problems with fuel starvation shutting me down.

As Jim C. and others have said, check your gas cap for proper venting, clogged filter or fuel line, or you may have a lot of sediment in the tank drifting over and closing off the fuel line.

[Lenny Bruce]

You’re exactly right!!! It was my fuel flow!!! Darn it all to hell I would have sworn electrical! Thanks everyone your all awesome!!

[mcgarrett]

As always, no charge for "expert" advice!

[Cape Codder]

I would just like to add a question to this discussion.
I like most everyone have a pencil filter in the top of shutoff fuel shutoff.

WHY?

The way I see it is that if my tank is full of fuel and I discover a clogged filter what are the chances of emptying the tank WITHOUT a mess ON THE SIDE OF THE ROAD?

Does it not seem better to just depend on the screen filter at the top of the gas fuel bowl ( '30 - '31 ) OR some even use a Modern Type filter.

Just a question I always have wanted to ask!!!

[Flathead]

I think the hope is that the fuel sloshes around enough in the tank to keep that vertical filter from clogging.

[Stingray70]

Originally Posted by Cape Codder

I would just like to add a question to this discussion.
I like most everyone have a pencil filter in the top of shutoff fuel shutoff.

WHY?

The way I see it is that if my tank is full of fuel and I discover a clogged filter what are the chances of emptying the tank WITHOUT a mess ON THE SIDE OF THE ROAD?

Does it not seem better to just depend on the screen filter at the top of the gas fuel bowl ( '30 - '31 ) OR some even use a Modern Type filter.

Just a question I always have wanted to ask!!!

You want to keep anything abrasive out of the shutoff valve. That stuff will eventually cause the valve to stick or not completely shut off.

[Fhane]

Easy fix. If you are on the side of the road with a clogged pencil filter.

Be careful of any dripping gas around a hot engine.

Turn off the fuel valve.

Just slightly loosen the fuel line at the sediment bowl.

Remove the fuel line from the carburetor and swing upwards so the end of the fuel line is higher than the fuel in the tank. Be careful not to scratch the fender and be careful of dripping gas on a hot engine.

Tighten the fuel line at the sediment bowl.

Turn the fuel on.

Blow into the fuel line to back flush the pencil filter.

Turn off the fuel and reconnect the fuel line to the carburetor.

Permanently fix when you can.

[Ramman]

That back fire you heard is what we always called a "lean pop". If you're familiar with an oxy/acetylene torch, what happens when you have a nice hot flame and shut the acetylene off first? BANG!

[oldspert]

I had the same problem with my 29. First and second gear was OK but when I went into third my car would go very lean. Found the gasoline I had bought the night before swelled the electric shutoff seal I had installed, so small no gas flow could get by. After it sat short while it would be OK until all of the gas in the carb was used.

[Y-Blockhead]

Originally Posted by Cape Codder

I would just like to add a question to this discussion.
I like most everyone have a pencil filter in the top of shutoff fuel shutoff.

WHY?

The pencil filter not only filters the gas, it raises the inlet to the valve ~ ¼" off the bottom of the tank so the valve doesn't clog.

[Big hammer]

Originally Posted by Y-Blockhead

The pencil filter not only filters the gas, it raises the inlet to the valve ~ ¼" off the bottom of the tank so the valve doesn't clog.

For all but the late 31’s, they lay in a trough, I put a strong magnetic to help keep rust away from the screen