Jim Ledford wrote:

the ones I've seen have no hole. since I've not seen them all
and do not know about all different types I'll add your input to
the list of new information I've received today.

Andy comments:

On the Murray I have, the gas is squirted when the primer
is pressed, and the air is brought into the bulb when the
primer is released. If there is a hole in the bulb, the thumb
covers it when the gas is squirted...

I had a hell of a time starting the mower at first because I
thought that RELEASING the bulb squirted the gas... I took
the air filter off and observed the opposite. Now when I
prime, I PUSH very hard and vigorous. Starts on the first pull
every time now.....

Just rambling on......

Andy in Eureka, Texas