For many many years, I had a cheap Murray lawn mower with a Tecumseh engine. I did NO maintenance to it...never changed the oil, rarely if ever cleaned the air filter...it just kept plugging along with no maintenance needs other than an occasional pull string.
When it needed a blade, I bought a mulching blade, brought it home and realized I had gotten the wrong size. Being a fancy man, I thought I would just get a brand new lawn mower, and retire the Murray.
I got a really nice Craftsman mower from Sears, with a bulletproof Briggs and Stratton engine. I gave away the Murray, needing a blade and a string, on Freecycle. I have never started my love affair with this mower. I starts temperamentally, the air cleaner constantly clogs, the screw holding the air cleaner on bent...the air cleaner is cracked...and little other niggling problems.
Recently my blade bent, so I went out and bought the identical blade to the one that is currently on it...matched the part numbers and all, no guess work.
Today I decided to cut the yard, so I went out and attempted to replace the blade. Removed the old one and guess what...the new one will not fit...not even close. SAME PART NUMBER...this is the correct blade...but it will not fit. I reattached the old blade to make do for todays chores and after getting the mower started, it vibrated HELLACIOUSLY!! The vibration was so bad that the deck cracked...or the deck was previously cracked and that contributed to the problem...but either way, I have a practically new Craftsman mower that will be going away ASAP. I must now find a new lawn mower.