🚀 go-pugleaf

> Now that cold weather is back again my 78 Accord has started having
> a problem under the following conditions: cold, wet weather and the
> car has been sitting for a long time (overnight).
> 					marc gates

If the car sits out all night, I might suspect that the carburetor
is icing up.  As you drive, there is much cold, damp air being pulled
in.  As it goes through the carb throat, it hits a vacuum and can ice
up.  (This is a big problem for aircraft flying through clouds at
near freezing temps.  They have engine de-icers.)

As you sit for a minute, the engine heat gets to the carb. and defrosts
it.  So the car starts and runs fine for the rest of the trip.  During
the day, the sun on the hood might just keep things warm enough (just a
guess).

When the thing stalls, I would immediately open the hood, take off the
aircleaner, and see if there is a film of ice inside the carb.  If so,
you've found the problem.  I am not sure how to fix it.  If it just
started, it could be that someone left off the heat riser tube the last
time they worked on the engine.  Or the tube could be broken.  This is
usually a 2" metalized hose from the exhaust manifold to the air
cleaner.  The idea is that it pulls air past the manifold (which gets
hot rather quickly).  Thus, a few minutes after you get under way, the
carb. is getting warmer air, and the icing doesn't happen.

There are other things here though.  One is a flap in the aircleaner
which shuts off outside air till the engine warms up.  Another is a
restrictor which forces exhaust gas to go through the intake manifold
before going to the muffler (again to warm things up).  Finally,
there are often thermal vacuum switches which control the above mess;
one of these could be sticking in the "I'm all warmed up now" position.

	Steve Falco