New to me roadster quit on us tonight, carb question.

[dmdeaton]

Ok, this morning I took a 30 mile round trip to Ron's Machine Shop in Shandon, OH to show them the car. Stopped on the way home and filled up with 5 gallons. We jumped in tonight to take a short drive and less than a mile from the house it started sputtering and finally quit. Got it started with choke and it idled for a while then quit. Pushing on gas pedal it is starving for gas. I am pretty sure after sitting since October last year and me filling the tank up this morning some crap is probably floated into the carb. Glass sediment bowl is full of gas with a few particles laying in the bottom. Put it on a rollback to get it home. I am going to pull the carb in the morning and check it out. 2 questions:

1. Should I put a inline filter temporary after the sediment bowl and change a few times until I get some run time? The fuel tank at time of restoration was cleaned and sealed. I have read pros and cons on this also. I plan to take carb apart in the morning and clean it out.

2. I plan to get a spare carb. Are the new Zenith's that our vendors carry any good? I know they are pricey. My other option is ordering a rebuilt from one of the vendors but I don't want to give up my carb for core as I intend to keep 2 carbs. What would you guys do?

[BILL WILLIAMSON]

Be sure to put a "pencil" filter in the top of the fuel valve, suppliers all have them. They're a GODSEND!
Bill W.

[Mitch]

The first thing i would do is determine if it's spark or fuel. Lets check this out right and not get ahead of ourselves by just replacing parts. Have you changed or done anything to the car engine wise since getting it? fuel line, points, adjustment etc
This could be as simple as a non venting gas cap

[dmdeaton]

Nothing yet other than check fluids. I will check if fuel or spark in the morn. It sure acted like fuel, just like running out when driving. Push gas pedal it fell on its face while moving, let up on pedal kept running for a bit. Was able to choke it to start again and would idle but starve for fuel when peddle pushed. Finally nothing. Sediment bowl is full of fuel.

[DaWizard]

You really don't need to remove the carburetor. The problem you have sounds like the gas cap vent is clogged, it will allow you to run until you create a vacuum in the tank then do as you said, you run out of gas. So, unscrew the line from the carburetor, place a receptacle under the line and turn on the gas, see how long it runs before it trickles, then crack the cap to see if it resumes a steady flow.

Make sure to NOT change the cap before doing this, if you move the cap the test won't work, unless you get it back to as tight as it was, or in the same place.

What gave it away for me was you put gas in the tank then had it happen. Tells me you tightened the cap to a point that you shut off the vent.


Heh, give it a shot, what ya got to loose?

J.C.

[dmdeaton]

makes good sense to check this. Where is the vent exactly, in the cap itself?

[dmdeaton]

This has a electric solenoid fuel shutoff also. Will check it too. I would think if that quit sediment bowl would be dry?
I am going to bed, stressed for the eve. Catch you all in the morning. Gave me things to think about.

[DaWizard]

Oh no, that glass bowl will always have gas in it.

[dmdeaton]

You are right, the bowl has no escape other than taking apart, gas flows over top of bowl. Silly me.

[DaWizard]

The Vent in the cap depends on if it is original or repop, but normally around the edges. I usually drill a single 1/8" hole in the center of the cap, no more problem.

[Mitch]

Test it with the gas cap loose or off.

If the problem still occurs try richening it with carb cleaner, i like to use the vacuum port for the wiper as the nozzle fits in there nicely. You can also do it directly into the air horn of the carb but it gets more messy that way. See if the motor stops its issues when inducing the carb clean. Dont over do it as it takes very little spray to determine. If you pull the choke half way that also can richen it but if the issue is in the carb that is not always a tell tale thing to try. I use a spark tester inline of the coil wire to watch the intensity and rhythm when the problem is happening..

Just for your info about buying a carb Berts Model A has the best and most reasonable available. They are nicely done and tested on a motor before being shipped. Your best bet is to stay away from ebay and the other carbs from the vendors.

[Nabco]

I agree with Mitch on Bert's rebuilt carbs, put one on my car 2 years ago and a couple thousand miles, have never had to touch it.

[Mitch]

This thread is a good read from our tech section

https://www.vintagefordforum.com/for...-and-misc-tips

[Steve Plucker]

If not gas related...try replacing your condensor.

Pluck

[1931 Flamingo]

I've had the electric fuel shut off sol get "gummed" up by the fuel. Disassemble the solenoid and clean w/acetone or spray carb cleaner. FWIW
Paul in CT

[dmdeaton]

thanks for the tips guys, I will dig into it in a few.
My job in real life is electrical machine control. If the wiring is done right and the components are reliable enough I have no problem with some of these upgrades. I also have no problem going back to the mechanical simple ways these things were designed. Only reason for a fuel solenoid is convenience correct?

[George Miller]

The solenoid is to make sure it does not leak gas in the garage. The orginal shut off valves are bad for leaking.
Good advice above. Always test to find out what is wrong before replacing parts.

[dmdeaton]

you guys kill me, I never would have went to the gas cap first. I took the gas line loose from carb and it was dry as a bone. Turned the key on to activate the solenoid and got barely a trickle. Loosened the gas cap and opened the flood gates. Put gas line back on, started and purrs like a kitten.

Cap looks like repop to me, too new looking underneath. I cant figure out how these vent. It has vent hole in center underneath, but looks like it has to vent through the gasket seal after cap is on. Is there a notch or something else supposed to be in the cap?

Thanks to you guys I am on my way to an easy fix. Thanks a bunch

[DaWizard]

Don't worry about how it is suppose to vent, just drill a small hole in the center of the cap and leave it at that. Unless you want to do the whole judging thing, I don't think anyone will notice, and if they do, oh well, you want to have fun with it!!

IF you go for the judging thing, you will need to find an original anyway and swap them out for judging.

[dmdeaton]

I don't care about judging, just want to have fun with the car.

[Mitch]

I hope you found it
That's one of the first things listed in that book i linked you to above.. The information is here it just needs to be read, so i am hoping having a tech forum makes that easier..
Keep us posted

[dmdeaton]

any chance of getting the pdf of that little book Mitch? Would like to print it and save a copy in my archives.

[Mitch]

I only have it saved in single pages. I can email them to you or maybe just copy them off the forum.

[dmdeaton]

I will save off the pages, thanks Mitch

[Tom Wesenberg]

Do you have the 1928-9 threaded cap, or the 1930-1 quarter twist cap?

Do you have an indented firewall with the gas valve in front of the firewall?

For sure start by making sure you have the small filter in the tank valve, and I've installed them on the indented firewall cars with no problem.

[dmdeaton]

quarter twist cap and gas valve under dash

[tbirdtbird]

some repop caps have a single rivet, allowing the parts to rotate on each other, and lose the indexing of the vent hole.
Get the 2-rivet repop cap, it solves that problem.
I have had to re-drill the vent hole in my single rivet cap. Right this second I do not recall where the vent exits

[Mitch]

If i remember the leather gasket turns and blocks the vent hole. My cap was venting nicely but i drilled another hole for good measure. This way i am certain to be EPA approved

[Patrick]

Sometimes the vent will get with rust and blowing it out will fix it. Other times it'll just rotate so it can not vent. Anyway its an easy fix, or, leave the cap kinda loose till it does get fixed.

Usually the electric shut off is used on the later indented firewall 1931's so the hood doesn't have to opened at every shut down. Other than that it becomes SOP to reach down and give it a flip.

[Tom Wesenberg]

quarter twist cap and gas valve under dash

In that case I don't know why the electric valve was added, unless they just didn't want to fix the original valve if it leaked. I lapped mine with toothpaste, and it hasn't leaked since the early 90's.

[Mitch]

You may have saw this already but here is a basic fuel system filtering thread from the Tech area. I always run those glass bulb filters that are mentioned...
It explains some of the things that were mentioned here, such as the stand up tank filter

https://www.vintagefordforum.com/for...tering-options

[BNCHIEF]

Tbird Mitch could you guys post some pictures of the caps ,differences and fixes ?

[dmdeaton]

I am also very interested in this.

[dmdeaton]

Surely the original caps didn't have this problem?

[Mitch]

Take a look at the underside of your gas cap. Many of the repos in service have a single rivet in the center of the cap. Next to the rivet you should see a hole, this is the vent hole. The vent hole has to go through three objects that are part of the cap assembly. Twisting the cap on and off the tank causes these three parts to rotate out of position and the vent hole can get blocked.

You can modify the cap by drilling an additional hole on the opposte side (being careful not to go through the roof of the cap). Thread the hole for a 6-32 screw and install with lock-tight. This will prevent the three parts from rotating out of position.

The suppliers sell an Eaton style cap which already has 2 rivets to prevent the parts from rotating