car stalling when coming to a stop

Been starting to drive a car I haven't driven much at all the past 8 years. A Pre war Packard with downdraft carb. It did have old gas in it which I drained out & refill with fresh. However, the carb was never run dry or drained, so the old gas was sitting in there several years. The car starts fine and runs pretty good, but when I go to stop at a stop sign, it dies on me. It always starts right up again and off I go. One friend of mine thinks the old gas turned to varnish in the float bowl and partially gummed up the carb. Do you think running seafoam through it will help? Spring is here and I'm sure there will more situations like this out there.

If you are running some E-10 which is the common gas today, the alcohol may work as a solvent and eventually clean out the car etc. Be sure you have a good fuel filter in it and change it. By the way, what is the fuel pressure at the pump or does it have a vacuum tank?

I'm amazed that it runs at all on gas that old...

yes seafoam may help,, it cant hurt..

adding some MMO cant hurt either

I drained the tank last fall and put fresh gas in. I wasn't trying to run it on the old gas, but some old gas was in the carb for a few years and that's what gummed things up I believe. Car has a fuel pump which was just rebuilt with supposedly an alcohol resistant diaphragm. I put some 93 octane in it today.

If your carburetor design has a vent tube in the intake throat, I'd use a syringe or possibly a small funnel and add a concentrated dose of SeaFoam or similar carb/fuel system cleaner to the float bowl, let it sit overnight, and run it some more, repeat a few times. Often this will clean out the smaller jet orifices.

Since you said the car is running pretty good, I'd say you got very lucky, and the car sat with ethanol-free gasoline in it.

If your carburetor [probably a Stromberg EE-22 or 23 ? ] does not have an air vent pipe in the inlet of the carb, just above the choke plate, then you might have to be a bit more creative, maybe remove the fuel line at the inlet of the carb and install a temporary fuel line and gravity feed some SeaFoam or other cleaner to the float bowl. IF YOU CHOOSE TO REMOVE THE FUEL LINE BE CAREFUL !! The float bowl is POTMETAL and will break easily !!

One other possible 'fix' would be to remove the idle mixture screws and using an aerosol can of carb-cleaner, spray generously through the jet, replace the mixture screw to it's previous setting. [before removing the mixture screw, gently turn the screw in until it bottoms, counting the # of turns to allow you to return it to this setting when reinstalled]

Start and run the car, it will run like it's flooded until the carb-cleaner is drawn into the engine and burnt.

Then repeat this on the other idle mixture screw.

Of course the obvious 'cure' is to remove the carb and thoroughly clean it, replace gaskets etc. But sometimes the in-fuel cleaners will do the job.

Interesting story [to me at least] I bought a 1933 Pierce Arrow 836, Club Sedan that had sat with 'reformulated' gasoline in it for over 10 years, the fuel in the tank had evaporated down to a 2" deep layer of goo, much like permatex #2 gasket goop. The fuel pump would pump, and the carb was not completely clogged.

Once I got the fuel tank cleaned, pump rebuilt, and the carb thoroughly cleaned, etc the car ran very well, with one exception: The inboard idle mixture screw was not anywhere near as sensitive to adjustment as the outboard mixture screw. The inboard was still partially clogged.

What I mean is that at a slow idle speed, the outboard screw would have a very noticeable effect on the engine speed and smoothness with just a 1/4 turn left or right of the 'sweet spot'. The inboard mixture screw could be turned in or out about a full turn before a noticeable change could be detected.. and I could not get the engine to run rich enough or smooth as it should with the inboard mixture partially clogged like this.

I re-rebuilt the carb, dunking it in some very strong carb dip tank chemicals, and it looked spotless, and I used 'tag wire' to fish through every passageway I could locate, and every jet had been removed, cleaned and inspected with a magnifying glass. But the inboard idle mixture was still partially clogged and not responsive to adjustment.

So I just lived with a slightly rough idle for years in this car, I did locate a spare EE-3 carb but didn't install it before the car 'fixed itself'..

On a Pierce Arrow National meet in Bartlett NH, one of our tours was to Mt Washington, and the opportunity was offered to take our cars up the mountain. I couldn't resist.. So I took the '33 Pierce up the mountain road, 1st gear all the way, I had to stop a few times to let the car's fuel lines cool down, to stop the vapor lock, and then proceed on up the hill.

Once at the top, we went through the gift shop etc, then proceeded on down the mountain. The decent was uneventful, just closed-throttle in first gear, using engine braking all the way, and a little wheel braking for some of the switchback turns. The only excitement was when the trans jumped out of gear in the middle of a turn, I seemed to have not enough hands for a moment there.

At the bottom of the mountain, we rejoined most of the tour cars that had not gone up the mountain. As I parked the car, I noticed the engine was idling quite rough, much more so than before the run up and down Mt Washington..

I opened the hood and thought the engine was running very rich, the outboard idle mixture setting was still correct, it was in it's 'sweet-spot'.. but the inboard mixture screw took over 1/2 a turn in [leaner] to smooth out the engine, and surprise !! the engine idled smooth as glass. I was able to balance a nickel on it's side on the cylinder head.

Apparently, descending the steep hill using closed-throttle engine braking for about 20-30 minutes had drawn so much fuel at much higher than normal manifold vacuum, that the fuel flow had finally after several years washed clean the idle passageway. And it's stayed clean ever since.

GLong

Neat story. Thanks for sharing. My car is equipped with a Stromberg EE-3 as well. What I may try first is running the car on fast idle (with the dash mounted hand throttle), removing the air cleaner, and spraying carb cleaner down the air horn while it's running. Your method of adding Seafoam directly to the float bowl and jet passages may be the next step. Really, the carb should probably come off at some point for a complete cleaning. It hasn't been off the car in almost 50 years!

Are you sure the float has not become porous and submerging? Old brass floats sometimes permit gas to permeate through the brass metal. A gas compatible coating can cure this.

K8096: if your Packard has not had the carb off in 50 years, I'll recommend that you remove it and clean it thoroughly. That's a lot of years of gas drying out in the carb when stored, a lot of very small bits of crud getting through the filter and settling into the bottom of the float bowl..

If the accelerator pump is working correctly, then you only need to buy a gasket set for the carb. It is likely that at least one paper gasket will get torn when opening up the carb.

On the EE carburetors, the bottom of the float bowl is about 3/8"-1/2" lower than the passageway that lets fuel into the main jets. What happens is this lower 'floor' acts like a sediment bowl, collecting bits of crud over the years. I've removed an amazing amount of stuff from an EE float bowl. You can do this clean out in the car, but it can be difficult to lean over the fender and sidemount spare. If it's an EE3 in a prewar Packard, it's a V12, isn't it ? That one is harder to clean on the car.

If your fuel level in the gas tank is fairlly low, you can add Seafoam or similar products to the fuel. And it might be high enough of a concentration to be effective. I'd not waste the money on adding the cleaner to a full tank, the concentration is just too low to be effective. just my opinion.

Where are you located ??

GLong

No, the brass float shouldn't have a hole in it. It wouldn't run at all if it did. It would be flooded. Yes, it's a twelve. I'll probably end up taking the carb off at some point and going though the whole thing. Thanks to everyone for their advice.