Stop in for a cup of coffee
Dam just found the owners manual and my answer, pretty cool.
H. SPOT TIMER (STITCH TIMER)
After the torch trigger is actuated,
the timer allows the wire
to feed and the gas and power to
flow for the time selected. The
Function Switch must be set in
the
"SPOT" position (or the
"STITCH" position for stitch
welding).
http://www.800abcweld.com/pdf/fm140a_owners_manual.pdf