Hard to start after sitting for a week

[DennisDressel]

I have a 79 Spider Fiat with a mechanical fuel pump. The car runs great. However, when it sits for more than a day or 2, I really have to crank the heck out of it to start! A day or less, it starts right up. I suspect the gas is slowly running out of the fuel line and it takes extra cranking to get the gas back up to the carb. The carb was recently rebuilt but this issue is still not corrected. Is there some sort of check valve that needs replacing? Thanks, Dennis

[SteinOnkel]

I too have this issue on my '78. Swapped to an electric fuel pump (it's pretty much in the same position as the mechanical one) and the problem persists.

If there is no check valve, perhaps we could just add one.

And here it is, for a whopping $5: https://www.ebay.com/itm/8mm-New-5-16-O ... 3758635770