Re: Hard Starting T'all

[jlandry@domain.elided (John A. Landry)]

In a brilliant stroke of genius, PB Schechter <pb@domain.elided> blurted
out:

>Yes--I have wondered about gas boiling out of the float boal.  Until
>just this minute, I thought that my seeing the acceleartor pump
>squirting fuel precluded this as the cause of my problem.  However, it
>has now occurred to me that the squirts might mean that there is fuel
>in the *line*, but not necessarily in the float bowl(s?).  I wonder if

It's my experience that the fuel doesn't completely boil dry in the bowl,
and especially the accelerator pump well.  I've had my carburetor very hot
(fuel boiling from the area under the jets), let it sit until cool and then
taken the carb top off (to change jets).  The bowls still had plenty of
fuel left.  Rather, I'm beginning to think the boiling may somehow
chemically affecting the fuel so it's less volatile, making it harder to
burn and thus start the engine.  Either that, or the super heated engine
and fuel causes an excessively lean mixture (due to very low fuel and air
density) which is making the starting difficult.  Then again, it could be a
mini-vapor lock situation inside the carburetor passageways (between the
jets and venturi).  I'm full of theories and no real solid leads.

>choke doesn't fill the float bowls any faster (I don't think).  I
>wonder if I should put in an electrical fuel pump....

I'm not sure if anyone with hot restart problem has added an electric fuel
pump to see if that helps.  I'm sort of thinking it wouldn't make much
difference myself... seeing how the bowl doesn't actually boil dry.

>By the way, I don't think I have EGR, do I ('65, remember)?

You probably don't.

>I would be tempted to agree with you here, except for the following:
>(1) My carburetor is *not* jetted rich!  If my memory is correct, and
>if my carb's rebuilder is correct, the original jets for the 2300 were
>55s, and my carb is jetted with 51s.  He (the rebuilder) claims that
>this is about correct, for 5,000 feet.  (2) I have a manual choke.
>There is little room for adjustment there, I think, short of assuring
>that it is closed when pushed in, and open when pulled out.

Got ya... except there *is* an important adjustment for a manual choke
which is easily overlooked.  The choke control you pull controls how much
the choke plate covers the carburetor throat.  The more you block it, the
richer the mixture.  However, at the same time you close the choke plate,
the throttle *must* be opened to some degree.  Normally, the choke linkage
on the carburetor is designed in such a way as to pull the throttle plates
open to a maximum of what is called the "fast idle setting."  It could be
that your choke is not opening the throttle plates at all.

On my Edelbrock, pulling the choke open also opens the throttle in a
coordinated amount.  But like your carb, if I pull the choke too far, the
engine will likewise die or fail to start.  Varying engine temperatures
require varying amounts of choke application.  A warm engine may
immediately die if the choke is applied to the same point that a very cold
engine will happily run.  This is due to the degree of fuel vaporization
and the engine's varying air / fuel mixture requirements depending on
temperature.

Check this angle out.

It also could be that while your jetting is perfect for 5000+ feet, your
idle mixture screws may be adjusted incorrectly yielding a very rich
*idle*.  This would have little effect on highway fuel economy.  Just a
thought.  Did you adjust your idle using the best lean drop idle method?

Regards,

John
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