Originally Posted by C&KLawnCare
Just run it , When i had my small engine shop opened full time , i can not rember how many of the 14.5hp to 16 hp one lungers i had come in here with the same thing , My 1999 Craftsman has the 14.5 Hp briggs and that sucker at idle has always knocked . Shove in on the clutch and it would ease up in sound let back out and was noisier, over 3,000 hrs later the SOb still is knocking at idle and still runs , I tore it completly down once cause it was bugging me . Damned if i know what it is cause their was not a thing out of spec nor loose. I think its in the spark timing making the knock my self . but since ya cant adjust it i guess it will just knock away
Briggs is a little sloppy with getting the crankshaft end play adjusted properly when they assemble there engines. Thats probably the knock you hear in yours and why it changes when you push the clutch,They have 3 different thickness gaskets and for really sloppy ones a special shim washer that can be installed on the PTO end of the crank to get a more precise end play adjustments. At one time they had a batch of 16 and 18hp twins get out the factory that knocked so bad they had to have the washer installed and proper end play adjustment before we could even sell the darn things.
Just thought you'd like to know a possible cause.