[AJD] Physics 101

[Karl Olmstead]

1.  Gasoline engines need a richer mixture in order to run when very cold. 
That's what the choke is for.
2.  Gasoline is less volatile, so the mixture tends to be leaner.  Some of 
the fuel puddles in the intake manifold or cylinders instead of remaining in 
the fuel/air mixture.
3.  Thick oil and grease make starter less efficient (human or electric).
4.  More probability of moisture condensing in the distributor or mag and on 
the plug wires, reducing voltage available at the tip of the sparkplug.
5.  Battery output drops very rapidly as the temperature goes down.

I don't think you're more likely to suck a gob of oil, but the oil doesn't 
want to be blown up into the filter portion of the air cleaner, so less 
washing of the filter element takes place.  Judging from what I've seen the 
past two weeks, you're much more likely to get water in the filter bowl, 
which raises the oil level and may cause oil ingestion.  I have a Farmall 
that is dripping oil out of the bowl for that very reason.  Gotta get it 
drained before it causes rust.

-karl
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> What is the physics behind our old treasures being harder to start in cold 
> weather?
>
> Is the ignition system affected by the cold?
> Is the fuel mixture somehow different?
> Is it harder to burn the fuel mixture enclosed by cold iron?
> The physical effects of the thickened oils are obvious, but are there 
> other issues with oils as well?
> What about air intake?  Any changes there?  Am I more likely to suck a 
> glob of oil from the breather into the carb during cold weather?
> Aside from the obvious effects from freezing, does the coolant system 
> behave differently during cold weather?
>
> My old John Deere tends to wake up pretty well on a cold morning, about as 
> well as I do, but the definition of cold here in Texas is different than 
> it is elsewhere.
>
> Thanks!
>
> Cal B.
> Nacogdoches, Texas