Intake manifold copper pipe p/n 1-05-13

D

DAVIS,BRIAN R

Guest
Does anyone know how that "heat riser tube" (1-05-13) works?

It's copper, (about 3/32" dia), screws into the intake manifold just below
the carburetor, makes an up and down loop, and just hangs there.

Bob Gordon says that it is to capture gas vapors that pool in the intake
manifold after the engine is shut off. He said that this prevents these
vapors from going down into the bilge and causing an explosion hazard.

When I attached a vacuum gauge to it, I got absolutely nothing. This tells
me that there's not even a hole into the intake manifold. I confirmed this
by unscrewing the tube and there wasn't any visible hole drilled into the
manifold.

How does this thing work?

Thanks!
 
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