HELP! When riding mower starts and I start to drive or shake it dead

I have a craftsman riding lawn mower with a briggs and statton 19.5hp turbo cooled platinum engine. Its an older one but its worked like a charm until beginning of spring. I mowed my lawn the first time with no issue. I go and start it up again 3 weeks later and it cuts and im almost done it dies. Every since then i go to crank it it will immediately start up and once i start to ride it slightly stalls and it goes dead and will not crank back up. I used starting fluid with success but eventually does the same. Ive replaced the fuel filter and yet its still doing it. I cleaned the carburetor and it cranked perfectly and i just left it to run in the garage for about 5 minutes. Sound beautiful. During this i started to shake the mower back and forth and it hestitated and died. It didnt crank back up. What is going on? I clean the carburetor 3 times and it cranks up perfect. I start to ride and after i go over some rough bumps or holes in the yard and it shakes the mower it stalls out and dies. Need help ASAP! I just changed my oil which was so black. I did notice after shaking the mower and it died i did take the oil dipstick out and the oil was all the way up the dipstick. Was it too much? It was obviously but would that be the reason .