On Oct 16, 3:49*pm, Puddin' Man wrote:
21" Yard Machines push mower with 4.5 hp Briggs/Stratton Quattro, about 12
years old.

Yesterday I pulled/sharpened the blade, cleaned the air filter, and changed
the oil. Old oil looked about the same as always after 1 full season.

Today I start it up, I get a CLANK-CLANK-CLANK proportional to rpm, and kinda
like a rod knockin'. Gets lots worse as I try to mow, so I stop and test. The
motor will turn over and start with the rip-cord, but it feels t-i-g-h-t. Oil
is clean and up-to-level.

Definitely a candidate for the junkyard, but ... what happened? Key sheared
off the flywheel??

* P

"Law Without Equity Is No Law At All. It Is A Form Of Jungle Rule."

This is probably not related to your problem but does your lawn mower
have a fuel filter? I also have a Briggs and Stratton and didn’t know
it didn't have a fuel filter until I had to take it apart recently. I
had to buy an in line fuel filter an put it in the fuel line because
the gas tank seal and fuel hose were disintegrating.