1949 Packard stalls after 2-3 minutes (Help)

Hi everyone, I'm 17 and recently bought a 1949 Packard, my grandpa and I took it in to a shop to make it road worthy. The car will start and run great for about 2-3 minutes or so and then will slowly loose power and stall out, we know it's getting gas, but we aren't sure if it could be the valve timing is off or if the valves are just gummed up, I could really use your knowledge on what you think it may be. Thank you for your time

- Brandon

I would wonder if the choke is opening. It almost sounds as if it is not and the car is running too rich. After a few minutes running the engine should be warm enough that a fully closed choke is not needed and should open. Next time it happens you might immediately pull the air cleaner off the carb and see if the choke plate is open or at least well on the way to opening. If it is then something else is causing the problem. If not, then it could be adjustment, faulty choke mechanism or heat is not reaching the bimetal element to operate the mechanism. Another thing that could cause rich running and the same symptom is a clogged air filter.

The carb was just rebuilt, so we are sure it's not the choke sticking, so I'm still thinking something with the valves, I would just like someones take on the situation and if a car slowly loses power due to bad timed valves or gummed valves? Thanks for your time

-Brandon

There are many things that could cause the stalling, but I would start with the simplest items first.

If it starts and runs, I think it is unlikely that there is a problem with the valves.

I have seen a plugged fuel tank vent cause this problem. I don't know if your Packard has a vented fuel filler cap or if the tank has a separate vent. Either way, a plugged vent can cause the car to stall after a few minutes. You can test for this by running the car with the fuel filler cap left loose or removed.

If it still behaves the same way, I would then verify that the exhaust system is not crushed or badly dented and that it is not plugged with rust particles, a rodent nest or an insect nest.

After a visual confirmation that there are no obvious restrictions, the easiest way to test for blocked exhaust is to disconnect the exhaust system at the exhaust manifold outlet and run the car for a few minutes with the exhaust system disconnected. If it does not stall, you can be fairly confident that there is a significant blockage in the exhaust system.

If it DOES stall with the exhaust disconnected, I would focus on fuel line blockage between the fuel tank and the fuel pump. The suction line (fuel pick-up) in the tank could be plugging up with rust and scale or the lines could be plugged with scale, rust or varnish. If that's what is happening, you will need to clean out the entire fuel system (tank to carb) to eliminate the problem.

Good luck!

Fuel venting and debris is a common problem many have encountered lately -- particularly if you have not cleaned the tank or have recently replaced the gas cap. Definitely worth checking. And if the exhaust and fuel venting is not the issue, revisit the choke.. If the carb was rebuilt, chances are mechanically it is OK but verify it is operating. Only takes a few seconds to look. Rebuilding the carb won't help if the problem is something external to the carb such as a blocked or corroded stove or air tube preventing full heat from getting to the choke.

Additionally, there is a choke flap in the exhaust manifold that if stuck closed will cause the car to behave as you describe. Be sure you can pivot this flap via the counterweight opposite the thermal spring on the other side. If you cannot pivot the flap, odds are it is stuck in the closed position (that's just the way the odds are for this component) You will need to take the manifold off to service this choke flap, sorry. Unless you plan to drive the car in cold weather, some people will suggest you can do without this manifold warmup device (choke). good luck!

Ok thank you everyone for your quick responses! So what you you all are saying is that it is most likely in the fuel system? Where Is the choke located in the exhaust system? Thanks again

-Brandon

The heat riser valve is located in exhaust manifold below the carb. There should be a spring loaded weight -- most likely weight is on the rear, spring on the front -- which will move freely if things are operating normally. If things are stuck then it sometimes can be a project to free. If it is stuck, don't go banging on it or use oil to try and free it. Either could cause more problems.

The heat riser valve is located in exhaust manifold below the carb. There should be a spring loaded weight -- most likely weight is on the rear, spring on the front -- which will move freely if things are operating normally. If things are stuck then it sometimes can be a project to free. If it is stuck, don't go banging on it or use oil to try and free it. Either could cause more problems.

Also make sure the riser returns when you move it - I've had the bimetallic spring break

Hi Dave, I have yet to put new points in the distributor. When the car starts dropping cylinders/losing power if gas is added it doesn't bring the engine back it just keeps slowing down and ultimately quitting. We are thinking the valves need timed/cleaned but we aren't sure yet. The temp guage is still cool when this happens. Thanks for your time

-Brandon

Change the condensor first. If that doesn't fix it change the coil. Very unlikely it has anything to do with the valves.

Ok I just ordered the distributor tune up kit so I will see if that solved the problem and I'll let you know.

Thanks

-Brandon

If the engine starts and runs OK and you are not getting a lot of back fire through the carb it is unlikely that the valves are either stuck or off time. When they go off time (usually due to a chain or drive gear failure) you get a condition where they will rev high, then drop way down low, then high (rinse, lather,repeat) with the throttle open almost all the way. They won't start with the throttle closed at all in any other position when the timing is off. I really don't think that's your problem. Another often overlooked thing is the flex hose between the solid fuel line coming from the tank and the fuel pump on the engine. Those get old, develop cracks and you can lose the prime on the system. Niagara Packards has re-made them in modern hose material, this is a good thing to do to insure reliability.

Thanks for all your help I will let you all know what we figure out/ if we get it running good!

- Brandon