AFTER ENGINE WARMED UP IT CHANGES TONE AFTER THAT POINT IT WILL NOT SHUT DOWN UNLESS YOU MANUALY MOVE ENGINE LEVER TO OFF
Welcome to Heavy Equipment Forums, Norman. You'll need somebody with more mechanical knowledge than myself to answer your question, and hopefully that'll happen shortly, but in the meantime, can you please not post using all caps? We have a Forum Rule against that, because in internet etiquette all caps is considered to be shouting. Thanks in advance.
Welcome Norman, is your engine smoking badly at all? Grey, not black like a diesel should? I've seen a lot of those engines run-on when they have a bad head gasket. Quite common. Not sure what you mean by "manually move engine lever to OFF." Key switch on the ground panel?