Re: Hot starting problem

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

rhughes@domain.elided scribbled in the sand:

>>>My 304 V8 starts instantly when cold. When warm or hot, it cranks very
>freely, but does not start without five or ten seconds of cranking.
>
>Gene, that might be something as simple as percolating fuel.  When the
>manifold gets hot, gas in the float bowl tends
>to evaporate, making it hard for the carb to meter fuel properly.  The
>simple fix for this is a thermal spacer between the carb and the manifold.

I'd have to agree with this diagnoses.  It's quite common actually in carbs
that have float bowls integrated into the carb body.  The carburetor absorbs
lots of heat from the intake manifold and the fuel boils upon engine shutdown.

If you can't find a proper heat insulating gasket for a stock IH (Holley)
carb, you could make your own by using thick gasketing material from a local
auto parts store and sheets of aluminum from a hardware store.  Using the old
gasket as a pattern, alternate the gasketing material and aluminum sheets
until the gasket pack is maybe 3/8" thick or so.  The gasketing material (and
not the aluminum) should be in contact with the intake manifold and carb base.
Do not over tighten the carb mounting bolts, or you risk breaking them off or
cracking the carb base plate.  Be sure to adjust the divorced choke rod
setting if the carburetor is raised higher.

Regards,

John
-------------------------------------------------------------------------- 
jlandry@domain.elided              |"If I could have gotten 51 votes in the
Conservative Libertarian         |Senate...for an outright ban, picking up
Life Member of the NRA           |every one of them, Mr. and Mrs. America
WA Arms Collectors               |turn them all in, I would have done it."
Commercial Helicopter - Inst.    | - Senator Feinstein on banning firearms
http://www.halcyon.com/jlandry/  |   in America, CBS's 60 Minutes in 1995