I bought a $99 Poulan push mower about 4 years ago.  I couldn't get it to run this spring, so I took the tank off and pulled the carb off and cleaned it out.  After a couple of times of taking it apart and putting it back together, I finally got it started and it ran wide opened for a couple of minutes . . . then slowed down and started surging . . . then died.  I had another old tank and carb I had saved from another cheap mower I trashed years ago, so I took the carb off of it and cleaned it out.  Got about the same results.  I gave up and went back to ACE and bought another cheap Poulan.  They've gone up to $149.     Anyway, I shoved the old one under the house with about 5 other old mowers I thought I might be able to fix someday.

When I was doing some research on the old Snappin' Turtle mower I bought, I ran across a video on fixing surging problems on these newer Briggs mower engines with the carb on the tank.  It showed doing exactly what I had been doing with one exception . . . the guy said no matter how good they look, always replace the diaphram, gasket and screen with new parts.  I filed that away in the back of head and went on with life for a few months.

The other day I was in ACE and saw the kit for this carb.  It's Briggs and Stratton part #5083 and cost 4 bucks and a little change, so I figured it was worth a shot.  It was.  This thing runs better than the brand new one I bought this spring.  The guy in ACE's small engine shop says he gets these mowers all the time not running, or running fast or surging.  He said most of the time all he does is clean out the tank and carb and install one of thes kits.  Takes about 15 minutes and all you need is a 1/2" and 3/8" wrench, a flat screwdriver and a #3 Philips (#2 will work if you are careful).