This is Curtsey of the:
The plunger stem rises after I pump it up.
How This Part Works:
At the bottom
of the pump plunger cylinder is a check valve. This device temporarily
keeps pressurized air from leaking out of the fount or tank, until it
is locked-out by the air stem. When you are pressurizing the appliance
the check valve will hold in the air during your up-stokes, and then
again before you have a chance to turn the plunger fully clockwise. In
the blow figure, the check valve is in light-orange. Note the small
check ball in the center of it, in bright yellow.
For more information go to our Theory of Operation chapter.
Why it is Not Working Properly:
Over time the
check ball and the inside of the check valve will corrode and varnish
will collect. This will create a situation where the check ball cannot
properly seat itself in the valve. If you pressurize the appliance and
then just rest your finger over the hole in the pump before you lock it
clock-wise, see if it raises. If it does then the check valve is
How To Fix It:
check valve is no easy task. But before you get worried I will tell you
that a "good" check valve is not required for the lantern or stove to
operate correctly. When you are done pressurizing it, keep your thumb
over the hole and keep pushing down and then turn the stem clockwise to
lock it with your other hand. Once locked, the check valve is no longer
in use and the air stem has the passage completely blocked off. If you
do wish to replace the check valve please refer to our Rebuild Instructions.