I have a 1978 carburated spider. Just prior to the mechanical fuel pump in the engine compartment and in the fuel line feeding into the mech fuel pump is a metal " valve " or perhaps a filter . The space ship looking thing. What purpose does it serve??? How can I test it to make shure it is good and working. the car runs fine once started but takes a long time to start if it sits for more than a few days. I can not blow air thru it in either direction with mouth pressure.

are you referring to these?

http://www.midwest-bayless.com/fullView ... 570-OE.jpg

Factory OE metal-bodied one-way fuel check valve for use in the fuel supply lines on most carbureted Fiat cars with mechanical fuel pumps. Fitted near the fuel tank to prevent siphoning of fuel back to the tank.

If your car requires a lot of cranking after sitting overnight to start, this could be the culprit.

This is the early "ufo" (flying saucer style) as original production fitment by Fiat.
OE style metal unit is very difficult to source.

Fully interchangeable with later style round body units.

Fiat USA superceded from metal ufo style to the unfortunate plastic-body round replacement which is prone to rapid demise.

http://www.midwest-bayless.com/storefro ... =255092515

Factory OE metal-bodied one-way fuel check valve used for the evaporative emissions venting system on most carbureted Fiat and Lancia cars.

This is the later round style as original production fitment by Fiat.
OE style metal unit is very difficult to source.

Fully interchangeable with earlier style "ufo" (flying saucer) units.

Fiat USA superceded from metal to the unfortunate plastic-body replacement which is prone to rapid demise.

it does not look like that but mine might be an older style. Also like I said mine is located in the engine compartment in the fuel line just before and feeding into the fuel pump. Also it is not in a fuel vapor line, it is in the actual fuel ( liquid gas) line. Does anyone know i.f these can be tested and how????
I can not find a way to post a photo or I would

Thanks for any help