I drive my 61 Valiant about once every 2 weeks on a club run and it is hard to start as the fuel has drained back to the fuel tank (I think).

If I drive it daily, say on a 5 day tour, it starts easily each day.

I am thinking of installing a 5/16" fuel check valve in the flexible fuel line just before the fuel pump.

Any pros or cons on the installation?

It's actually the fuel evaporating out of the carb.................

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Ed
64 Valiant 225 / 904 / 42:1 manual steering / 9" drum brakes

Ok.

How can you stop the fuel evaporation?

depending on the carb, it could be fuel draining into the manifold.

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-MattMan
LEANED & MEAN