I have five Walker's with Kohler engines. WHen I went by the dealer on Thursday he said Kohler had upgraded the breather tube (tube between crankcase and carburetor) because there had been some problems with cracking. My mechanic said he had rebuilt several engines because of cracked breather tubes. He suggested I change all of mine. I checked two this morning and both had cracks, so I replaced them. I will replace the others in the next few days. I had had a couple of engines fail because of breather tube problems, so I am taking no chances. I just thought others might be interested in the information. The may be old news. if it is old news, I apologize.