Small Engines (Lawn Mowers, etc.): LAWN MOWER, gas cap, hi john

Question
I HAVE A SCOTTS PUSH MOWER IT HAS A PRIMER BUTTON .IT WILL START AND RUNS.  IT SURGES UNLESS I HOLD THE PRIMER BUTTON IN WITH MY FINGER THEN IT RUNS SMOOTH ? I CHANGE GAS CHANGE AIR FILTER AND CLEANED CARB,ONLY HODING RUBBER PUSH BUTTON MAKES IT RUN NORMAL THE BUTTON DOES NOT APPEAR TO HAVE ANY HOLE'S
PLEASE HELP

Answer
Hi John,

Try to keep it running while squirting fuel or starting fluid into the carb intake.  If it starts and you can keep it running by adding fuel, then the carb most likely has dirt, debris or gummed fuel inside.
First, check the gas cap to make sure it is venting and not causing a vacuum in the tank.  If that's okay, you will need to remove the carb, disassemble it, clean all the small internal openings and blow it out with compressed air.   Probe each and every hole with a small wire.   A carb rebuild kit wouldn't hurt either.  

Let me know how you make out.
Michael