What is the possibility it is the safety switch under the brake pedal, I took it out and held it in manually and it will stay running and will drive fine. As soon as I let go of that switch, everything dies... You mentioned safety switch under seat, I also found out I can not engage deck. It tries to start blades but will kill the motor. Motor seems to be running at full capacity. I should have added in 1st post, I have the 26 hp. Briggs. Thanks