Not sure what happened. It wasn't anything carb heat, electric fuel pump and switching magnetos could fix. Happened 5min after switching tank from R to L. Didn't think of it at the time, but I should have switched tanks again to see if it was my left tank fuel line was clogged, or here in ATL we have received so much rain, there may have been water in the fuel i pumped that morning (pumped Left tank first), or water in the fuel bladder, which didn't show in pre-flight. I am sure FAA and NTSB will let me know in due time. Got stacks and stacks of paperwork to fill out now. Managed to get 9.8 hours is my beautiful bird. Miss her tremendously.