Briggs and Stratton EFI 11.5 hp Powerbuilt
I am having a problem with my brush cutter. The machine is a Swisher Predator, 24 inch Rugged Cut Brushhog. It is slightly over a year old and was bought on Amazon. The engine is a Briggs and Stratton EFI 11.5 hp Powerbuilt. Pull start only. There are approximately 20 hours on the machine. It “seems” in good shape, and the previous owner said he did not have any problems. I bought it with about 10 hours of use. It has not seen any hard usage, though I did tangle once with a hidden metal fence post and the engine cut out, but it kept working after.
The issue is that the machine runs great for about ten minutes at full throttle (20 minutes if it is set to a lower throttle). After that, it will stall out if under any minimal load of light brush; and after that, it stalls even if not under load or the blade is engaged every five minutes or so. It always starts right up afterwards. The stalling occurs more frequently the more the machine runs.
As suggested by support at Briggs and Stratton, I replaced the fuel pump, but the same issues occurred. I have tried loosening the gas cap to see if there is a vacuum issue (though I have not replaced the cap). That also did not work. I drained the old gas and put in fresh, and I changed the oil and replaced the two belts. The fuel filter seems fine.
Right now, I am stymied and hoping that maybe it is still under warranty. I have never worked with an EFI small engine, and I wonder if there is a fuel injection issue, but that is just speculation based on my own ignorance. I am hoping that you might have a couple of other options that are worth trying before I bring it to a shop.
Any thoughts would be appreciated.
Thank you for your time,