NYLefty wrote:
I've somehow lost the cap to the gas tank on my Sears Craftsman push
lawnmower. I found a container cap that fits, but if I use that on
the gas tank the mower quits soon after I start it.

I assume that I should bore a hole in the replacement cap to let some
air in, .but I'm not sure how big the hole should be. Should it be as
small as possible to avoid gas splashing out? Could it be too small?

And I'm out in the country and weeks go by before I'm anywhere near a
lawnmower dealer, but should I eventually get a "real" gas tank cap to
replace my improvised one?

Keep your eyes open for someont throwing away a mower and grap the cap? Or just
buy one at any hardware store?

You could drill a very small hole in the cap, and make a cap washer for it with
a tiny hole in that too. You could cut the washer out of a clorox jug or similar
plastic. That should eliminat any spillage.