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I am glad you were able to clean the bowl and get the jet out. GUM Out will help remove the varnish/gunk from the jet.

I have a inline filter about 4 feet from my fuel pump in the frame channel. I use a clear plastic one so I can tell if it gets too dirty. I change it once a year.
I also have the glass filter with the brass mesh but the inline filter is much larger and gets most of the junk.

Gar

A few years ago I cleaned out and painted my fuel tank on my 31, which had lots of crud, varnish and rust dust inside. I got it really clean, but did install a glass fuel filter that seems to possess a finer mesh than the mechanical fuel pump sediment bowl. The bowl and screen seems to get the larger bits of grit, that comes through and the glass filter gets the finer bits. I installed filter between the pump and the carburetor.

So just when you think you have it licked…

Since the last update, I took it to a car show and it did quite well - 35 miles of city driving that day without any issues. Then I didn’t take it out for a couple of weeks, and when I tried to start it up again…same problem. Frustrating.

The solution from before of cleaning out the carb jet didn’t fix it. So then today I finally had time to do a more in-depth cleaning. Completely took out the carb, disassembled all the components and cleaned what I could, reassembled everything…still wouldn’t start.

So then I thought to just add some fuel directly into the float bowl, and voila! It ran for…about 20 seconds which I assume was just long enough to burn through the fuel in the bowl.

So here’s where I’m at - I’m certain there’s fuel in the gravity tank. There was significant gunk in the bowl under the tank, so currently I wonder if the fuel line has become clogged. I know that would be a lot of gunk, but it doesn’t seem that the fuel is getting from the gravity tank to the carb. Unfortunately the bolt connecting the line to the gravity tank is fused pretty solid and will take a lot of work to loosen. Which may mean taking out the whole gravity tank too, which may not be the worse idea in any case as it seems there might be significant crap in there at the moment.

And seems like I need to start thinking about a longer term fix to this too given the ongoing headaches it’s causing.

You'll have to locate the fuel delivery problem and correct it.

Pictures of the offending bolt may bring suggestions as to how to deal with it.

The entire fuel system, tank to carburetor, will have to be clean and free of any leaks or obstructions for the car to run dependably.

The vacuum tank can fail to operate even if it has some fuel in it. If there is any sign of debris in the vacuum tank, it will need to be cleaned and serviced as necessary.

***The vacuum tank cannot operate without manifold vacuum, so it may be beneficial to prime the carburetor as you did previously several times. That may allow the engine to run long enough to permit the vacuum tank to refill itself and keep the engine running.***

I'd want to be sure that there is at least 5 gallons of fresh fuel in the gas tank.

Also, verify the tank gas cap vent is not blocked.

So after a few more hours working on this I figured out a couple of things, I think. While I’m still not sure what was keeping it from running a few days ago, I’ve now confirmed that fuel is getting from the gravity tank to the carb. Removed the fuel line and no obstruction. But then I found that, now the gravity tank was bone dry. I think the problem there is that when I took the carb apart and put it back together, there was a damaged gasket that I didn’t replace, here:

Without that gasket it has been slowly dripping fuel, which eventually dried out my gravity tank (thus why no fuel getting to my float chamber, to state the obvious).

I’ve order a replacement gasket set from straight-eight.com, so once that’s in I’m going to put it in and hopefully that will fix the slow drip - everything else seems to be doing OK now.

(BTW big kev, thanks for the tip I did check and there was no obstruction of the pinhole gas tank vent.)

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If your carburetor leaks the bowl dry, the engine won't start, and if it won't start and run for half a minute or more, the vacuum tank cannot function. If the carb drains dry, the vacuum tank will also drain dry. The engine will have to run for some period of time to replenish the supply of fuel in the vacuum tank. I'm guessing that would take 30 seconds to a minute or so. Normally, the vacuum tank and carburetor would both be full of fuel at startup, but a leak would defeat that. Gasoline leaks are a fire hazard, besides the annoyance of having to prime the vacuum tank when the car has sat.

Yes, thanks for the reminder re: the fire hazard. I’ve shut off the fuel supply from the vacuum tank to the carburetor until I can get the drip fixed - hopefully the new gasket will do the trick.

Before I found the drip I’d refilled the vacuum tank and it ran nicely for a couple of minutes before I spotted the drip, at which point I obviously shut things off immediately.

With the leak fixed, it would probably be a good idea to shut off the valve between the vacuum tank and the carb whenever the car is parked overnight or longer. That will limit leak potential and help assure that the vacuum tank will be full of fuel, which should be enough to prime the carburetor and run the engine long enough for the entire system to be primed, even if the car has sat for an extended period. (Provided the fuel stays fresh)

So, I’m hoping this will be the final update needed on this. I’ve replaced the gaskets in the float chamber and under the nozzle, and seem to have stemmed the leaking at the bolt under the float chamber. However there is still a small leak from the bolt below the carburetor nozzle. While elsewhere in the carburetor the gaskets are made from what seems like a cork (or maybe just cardboard), this gasket (so-called in the parts list) is a metal washer. And I’m not able to get a perfect seal here, thus the leak.

I’m wondering if there are suggestions for how I can get a better seal on this bolt - e.g., a thread sealant product such as these:https://www.permatex.com/product-category/thread-compounds/thread-sealants/

I want to be able to remove this bolt again in the future if I need to access the carburetor nozzle, so I definitely don’t want anything that will create some sort of permanent seal. Thanks again.

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