My 20hp Briggs lawnmower hunts up and down and won't idle. It needs choke to keep running. It happened suddenly after I finished mowing one day. Is the carb shot?
Hi you might want to pull the float bowl of the bottom of the carb and spray with a choke and carb cleaner. Remove the jet in carb also clean then blow them out with your air hose. Replace with fresh gas and go mowing. Something else I ran into awhile back that was way different the gas cap on our mowers have a vent built into them I had one that was actually clogged causing it to run on choke only.I'd do the carb first tho and blow out the vent just because.