Packard Forum Index » Post-War (1946-54)

Don't know where you measured 175F, but >140F is hot to the touch, where you'll pull away. Ethanol gas doesn't like that temp range and this car was not designed for it. Not sure if it's fuel starved or fuel rich that's causing the stall. Insufficient info.
Ethanol gas was found to co-distill with certain mid-fractions in the base gas so it's boiling curve is much flatter than the old gas. So that's what's flashing. I'll dig up my file and post, not sure where it is right now. I'm a bit puzzled that the electric pump isn't maintaining pressure in the line which will suppresses vaporization. The float maybe by-passing either too much pressure or the seat is gone. I like to add a fuel pressure gauge so I can see what's going on. They're only a few bucks and tee into the fuel line before the carb. If it's too much pressure, blowing by the float, then you need a fuel pressure regulator.
If you have non-ethanol gas locally, that's the easiest fix, since you're in the low compression engines.
Low compression will only affect the ability to pull into the engine, aka vacuum. Won't affect ignition. Higher the compression, harder to fire.

Just a thought...out here in the desert, many of us run a gallon of diesel to a full tank of gas or a heavier amount of Marvel Mystery Oil in our gas...87 only...no higher octane. It does seem to help. You do need the insulators between the carb and the intake manifold and the heat shield...they do help. Miss Prudence has a shield at the fuel pump and the carburetor. She runs a bit heavy on the Marvel Mystery Oil...Ernie in Arizona

Ok so I can't get non-ethanol gas in town, so I tried premium 91 octane and it kind of worked. the vaporization point seemed to have changed. I also changed out the fuel filter which was pretty restricted. Now I'm installing electric pusher fans to keep the temp down around 160-170. I still think I'm having vapor-lock issues or maybe a stuck float, because it still dies when I come to a stop after driving and the filter seems to be draining when hot. I will most likely rebuild the carburetor and check for insulated spacer. I believe the 3/8in stock spacer is there.

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Mike52_200

I noticed the date of the first mention of percolation was the first week of April, or just about the first few days with afternoon temperatures above 90°F in the southern half of Arizona. You may have a situation of using winter blend fuel when the temperature is warm . . . not that 90°F is all that warm for those of us that live in Zona, but for winter fuel it would be. Given the few miles I drive my Packard, I’ve found myself driving during late in May (100+) with fuel I bought in February . . . normally my ’48 doesn’t like that, but my ’54 still runs OK. Do you have any idea when you last re-fueled the car?

Since the fall of last year, I’ve been adding the recommended amount of MMO for every re-fuel. Perhaps this summer I’ll have some results to report. As soon as I started doping the fuel, I noticed a trace of smoke while the engine warms-up . . . nothing after the engine is at operating temperature.

Perhaps we need a new thread, “Why my car doesn’t run in the summer”, especially for the Zona crowd where summer starts the first of April and runs until late October.

dp

Thanks for the information. I have been working on this 52 since I got it back in December of 2021. had the trans go out a few months ago, which I rebuilt and have been working on the gas issues for a few weeks. so other than a few gallons of gas I have not paid attention to when I filled it up. I just put 12in electric pusher fans on the new radiator I put in. I also changed the gas to high octane 91%. It seemed to help a little. now I'm dealing with heat and possibly stuck float or percolation issues. I think carburetor rebuild is next in order. what fun!

Throwing parts and accessories at it doesn’t solve the underlying problem so best focus on what is actually wrong and fix it. Then if you want to add fans or anything else, you’ll know that it won’t suddenly stall on you unexpectedly.