I bought this brute lawnmower from Wallmart 2 years ago.Self-propelled rear wheel drive.After one year it got to where it usually starts right off then sometime within the hour,plenty of gas stabil cartridge new plug and filter,then the engine just starts slowing down down down down and dies.It may slow down for several minutes then dies.I have had it to 2 different b&s dealers and still runs the same.The last time two weeks ago it was at dealers for 2 weeks.The mechanic brought it out running and I brought it home.I mowed 1 yard and it died.About 3 days ago I called the dealer and told them what was going on and he said bring in back if its something they did or didn't do they would make it right. I expected be be charged for it so I took the top off to look at it.Guess what everything around the carb and choke were greasy and dirty.Absolutely no sign of anyone working on it. OK.thanks for listenin g. Does anyone have any idea whats going on with this mower? I bought this in 2012 Brute with 7.25 engine .I forgot to tell you the mechanic told me they had to order and replace the thermostat on the choke.I never knew a lawnmower had a thermostat.I can't find one on any parts list. I really need some advice on this. I've done everything I can think of and seen online for possibilities for remedies. Thank you and would appreciate any ideas.It starts but won't run a hour without dying.NOt a gas problem or plug or filter

 

Sounds like a fuel delivery problem. I'd look at how fast the fuel is filling the bowl. It may have a kink or swollen spot in the fuel line, something blocking it in the tank or carb inlet, or could have a blocked vent in the gas cap. Loosening the gas cap when it starts to die would let it rev back up if that is the problem.

Many engines do have a thermostat that opens the choke when the exhaust temp gets warm.