It is in an woods lawnmower. After I mow for a while It will just stop. What do you think Is wrong with it. Tanks

Hi,
Often problems with the fuel pump or filter (or both) will cause the problem you describe. Fuel does not enter the carb as fast as it is being consumed. Sometimes this is only under load (when the engine is actually being worked) and will not occur when just running.
I would not think ignition since it has two armatures and would run badly if one failed.
A long shot is the fuel shut off solenoid getting hot. Another very strange one I have seen is that the fuel shutoff (if one exists) on the bottom of the tank may turn past the On position and reduce the flow.
Peace,
Clarke

I just finished installing a new Briggs fuel pump on my 24 horse that was doing the same thing.. Past history of mine goes like this. Operating for about 45 minutes the engine just died. I go inside and get a drink, rest for 20-30 minutes and cool down. Back in the seat and cranked up and I go again. 20 minutes the same thing over and over again. Well the little red fuel filter had to go. It was replaced with a slightly larger fuel filter... Next season and a few mowing's later this piece started it again... I pulled the carb apart and replaced the float and the needle that shuts off the fuel when the bowl fills. This was done at the advise of a certified Briggs repair center. I was also told to pull the solenoid from the bottom of the fuel bowl and cut the flat disc from the pin and that would solve any problems that I might encounter... Yep! That was wrong. Now when the engine is really run hard cutting in extreme heat and I decide to cool off for a few. When I shut the girl down it diesels and you think that you are going to loose everything in the engine... The solenoid only costs about $ 65.00 so we now pull the throttle all the way back to an idle and after about 3 minutes off with the switch and maybe it just dies... The long and short of my problems now? The strainer in the tank outlet stops up with some minute particles from who knows where and the fuel is not totally cut off but not enough fuel gets to the filter and then to the carb to keep her running under a load... Now whether you pull the tank and clean it like really good or you just let the new larger fuel filter you now have collect the debris. You got to look at this end of the fuel line chain... Hope this helps... this is from experience.. Power is from "above".
Mac