engine gcv honda put new valve in it and put block back togather runs great and sounds great but after it runs for 10 miniutes it sounds like somethings geting tight and the engine stall and dies it dont make any noise geting tight IT JUST SLOWS DOWN AND DIES i can pull on it its not locked up but i have to wait for it to cool just a littel and then it will run again ..............could the valve i put in be to tight ?? ANY HELP

might be the coil or whatever ignition sys it has. Do you have a spark tester? if you do, or can get one, hook it up, start the engine, and see if it has spark as its dying.

Yeah, it sounds like a failing ignition coil, test for spark right after it cuts off...