Packard Forum Index » Pre-War (1899-1942)

'39 Packard Six - 245 ci flathead inline 6 - The warmer the engine is from driving a few miles, the faster the idle becomes. I sought to perhaps adjust what I believe to be the idle screw - see attached photo, but it is too tight to be adjusted with my fingers, and the screw is positioned on the carb in a manner that makes it impossible to be accessed by even a stubby screwdriver. Using a pair of pliers seems rather crude. When the car arrived here in Oregon (elevation 4140') from Florida, it would not idle without some additional throttle. I had my mechanic tune the carb. More recently, the engine also begins to bog-down intermittently and lose significant power at highway speeds, and sometimes just dies, forcing me to find a shoulder to pull onto. Usually it can be restarted. I replaced the aftermarket electric fuel pump, because it's output was just dribbles and spurts. There is not a fuel filter installed, yet. Before I installed the new fuel pump I blew compressed air through the fuel line from the output side of the pump to the carb, with the line disconnected from the carb. There is a fuel pressure regulator just upstream from the carb. It was set @ 5. I adjusted it down to 4 in the hope that the black smoke (maybe unburned fuel) coming from the tailpipe would be reduced. At lower rpms/mphs the car runs better. Perhaps my issue is ignition-related, and replacing the coil, distributor cap, plugs and associated wires, rotor etc, is next. They look (I know looks can be deceiving) to be in decent condition. Can a forum member refer me to a source of these components? The auto parts chain stores do not seem to support old vehicles well.

I had very similar issues with my '37 and my '40 (I'm in Spokane). I bought a couple of WA-1's off of ebay, rebuilt them both, and the problems were solved.

To be brutally honest, I have no idea why the rebuilt ebay versions worked, when the rebuilt carbs that were on those engines did not. I never did find ANY difference in them.

I think I paid about $40 each for the cores; the rebuild kits were not expensive either.

Double check to ensure you don't have any vacuum leaks. My '37 was a wreck in that department.

Edit: Both of my WA-1's were quite a bit later--like late '40's, and one as I recall came off a Jeep.

if I'm looking at the picture correctly it seems there is no heat tube to the choke.
sounds like your choke is staying in the closed position hence the loss of power and cutting off and also the black smoke coming from tailpipe. take a look to make sure choke is operating properly.

Black smoke indicate too much fuel.... most likely a carburetor issue. Spark plugs may be fouled, too.

I believe Tom has nailed it. There is nothing to make the choke go off.

Tom, or others in the know, where does the heat tube connect to the choke and to the engine? In the attached photo, the position of what I believe to be the choke (the valve suspended across the top of the carb) is where it is when I attempt to start the car when the engine is cold - outside air temp is 58 degrees F. I must say it is difficult to get the engine to start. Also, does anyone know where to adjust the idle? I am inclined to suspect that there is a relationship between a very fast idle speed, black smoke, and the engine losing power and bogging-down.

The picture shows the choke in the open position. Does it close when you open the throttle with the engine cold? It should close with the engine cold when the throttle is opened, even if the engine is not running. The choke heat tube connects to the black object on the side of the carburetor and leads to a point somewhere on the exhaust manifold. If the choke does NOT close, pumping the accelerator may help the engine start. If the choke DOES close, holding the accelerator to the floor after cranking for about 3 to 5 seconds may allow the engine to start. (Continue to crank after pushing the pedal to the floor, and release the pedal the moment the engine starts)
For the car to start and run properly, the automatic choke must work properly and the manifold heat valve must also work properly.

As a temporary measure, the choke can be adjusted so that it will not open, and the car can then be started by pumping the gas pedal a few times before cranking it. The engine will need to warm up a minute or two when using this method, but it can get you by until the problems can be properly sorted out.

Tx,
The choke does not close when I open the throttle with the engine cold. Where can I find this manifold heat valve you mentioned? Is it an internal component of the choke assembly? Referencing the attached photo, there is a hole in the top of the exhaust manifold, likely where one end of the choke heat tube would attach. I have not been able to find a photo of the heat tube that was used on this engine/carburetor design, to be able to acquire or create one. In the second photo, there is a capped fitting at the base of the choke assembly, which I am assuming is to attach the other end of the heat tube. Can you confirm my understanding of this relationship?

I believe you are correct on the heat pipe attachment point to the exhaust manifold and the choke housing. The other end of the heat tube would connect to the device with the black plastic cover, which is the choke thermostat housing and which is where the choke adjustment is made. Apparently someone disabled the choke for some reason, perhaps the missing heat tube, by adjusting it all the way lean. The manifold heat valve is located in the exhaust manifold above where the exhaust pipe exits. There should be a cast iron weight on one end of the shaft and a small, coiled thermostatic spring on the other end. These devices are typically stuck due to corrosion. If your carburetor choke stays wide open with the engine cold, it may cause hard starting but it would not cause issues once engine has warmed up. The black smoke must be related to some other carburetor issue or a problem with the breather. Poor performance in cool, damp weather could be related to a stuck heat valve allowing carburetor icing, but that would not explain the black smoke. Are you certain that the gasoline in the tank is fresh? Stale gasoline can cause a variety of problems.

Thanks for the confirmation on the configuration of the missing heat tube, and the location of the manifold heat valve. I did fill-up the gas tank not long after I acquired the car last month. On the advice of other forum members, I use only ethanol-free unleaded gas and add a lead additive. The only grade of ethanol-free gas available here is premium - it is the same gas I use in my motorcycles and other power equipment (snowthrower, lawn tractor, etc) that some times sit for months unused, as it tends to not go bad and gum things up.