"One-way" fuel line valve..?

French demon said
Hi all
My 198 slant starts very easily and fast when hot, but when it has been shut off for a couple of days, I have to crank several times to get it back to life. The time required for the mechanical pump to refill the fuel line and the carb bowl.

I planned to install an electric fuel pump, but I would like to try an alternative and easier solution : a "one-way" valve (or "non-return" valve) on the fuel line. It's cheap and very easy to install.
But is it efficient? Will it prevent the fuel line from emptying (or will the gasoline evaporate anyway?)..? And where's the best location to install it on? Just before the fuel filter?

A typical "one-way" valve :
View attachment 1716161250

François

It's probably just evaporation. Trying a check valve wouldn't hurt. We have had many discussions here about the subject and the only fix people rave about is the electric charge pump. Those that have tried the check valve don't say much about it after it's installed. Here's a link to the pump thread. Hook it up near the tank with fused power and a momentary pushbutton. Electric primer pump for fuel