[DeTomaso] Why is it hard to start cars that havebeensitting for months?

[Julian Kift]

Hard starting can be pretty typical of a carburetted engine, a number of issues can come into play over extended stagnant periods, here's some food for thought;
 
1. Fuel starts to go stale after about 30 days, ethanol blends are worse.
2. Alcohols (Ethanol) are hygroscopic so absorb moisture over relatively short time periods.
3. Carburetor fuel bowls have evaporative losses
4. Mechanical fuel pumps take cranking time to build a constant fuel pressure
5. Fuel leak down from the carb into the intake manifold (and to cylinders unevenly) can ocur
 
Personally I find the evaporative losses combined with mechanical pumping to be the biggest issue, I never had much problem with cars running electric fuel pumps (carburetted or injected).
 
Julian
 
> From: charlesmccall at gmail.com
> To: asajay at asajay.com; detomaso at realbig.com
> Date: Wed, 12 Jan 2011 21:22:36 +0100
> Subject: Re: [DeTomaso] Why is it hard to start cars that havebeensitting for months?
> 
> okay, so if it smells like fuel, then my bet would be an over-rich 
> mixture when cold. 
> ****If that were the case, it should do it after sitting overnight if I
> start on a cold morning. This isn't the case (despite not having a choke).
> It only starts cylinder-by-cylinder if it has been sitting for months. 
> 
> Maybe, maybe not. Either way the problem is most likely either too 
> much fuel or too much oil in the cylinder.
> ***Too much fuel is a possibility, but why? 
> 
> Don't wait four months this time, wait one week and see if the problem 
> is the same.
> ****Well I hope I don't have to wait 4 months, but temps are back around
> freezing so I'm not sure I have much choice. In any case, "problem" is
> relative - I'm not really suffering a problem, am just curious what is
> happening. Thanks for the ideas!
> 
> Asa Jay
> 
> Quoting Charles McCall <charlesmccall at gmail.com>:
> 
> >
> > What color was the smoke that filled the garage?
> > What did it smell like? Oil or fuel?
> > ***It wasn't oil smell, it was fuel.
> >
> > Typically this would be caused by a bit of oil leaking into the
> > cylinder which makes it harder for the spark to ignite the air/fuel
> > mixture. After a few minutes it all burns off and you're good again.
> >
> > As I recall, you had the heads serviced a while back. I presume it got
> > all new valve stem seals, did they get the stock umbrella seals or
> > positive lock type?
> > ***Nope, my heads were built, rebuilt, and built once more back in 2001 or
> > so. I'd have to look and see what kind of seals he used, but since the
> smoke
> > isn't oil smoke I'd assume that they are in good shape
> >
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