Blew up my lawnmower -- Carnage oics

[metalmonkey47]

So our 20 year old Briggs and Stratton 12.5HP riding mower went out with a bang tonight. We'd be hearing a slight crankcase rattle out of it for the last day or so, so I changed the oil and topped it off...

 

Used it all day today without a problem until there was a split second rattle and it made a very abrupt loud series of bangs and shut off.

 

 

 

Thought you guys might like to see the results from the autopsy. :thumbup:

 

 

 

 

 

As you would think, the rod was what broke. But the question is, why? Surely the rod wouldn't just break with no reason. And why would we hear rattling and be able to use it for nearly 12 hours before it broke?

 

Surely it had another problem...

 

 

Here's what we're working with. a standard 12.5HP Briggs 'n Stratton motor with the case freshly cracked.

 

 

 

 

 

As we expected, the rod was in pieces. No scoring to the aluminum case or to the cylinder walls.

 

 

 

 

 

 

 

^^ BUT wait, what's that big broken thing there in the last picture? The counterweight. Shattered into two pieces. The counter-weight link was broken in half as well.

 

 

 

 

 

 

Now that we can see what else it broken, lets look back at the rod, because it broke in such a cool way.

 

 

 

 

 

 

 

 

 

 

Surprisingly no scoring to the crankshaft. Dunno how, but whatever.

 

 

 

As of right now, we're missing a chunk of the rod as well as half of a bolt.

 

 

 

 

 

The determined cause of self-destruction?

 

 

 

 

dum

 

 

dum

 

 

duuuuuuuuuuuuuuuuuuuuuuuuuuummmmmmmmmmmmmmmmmmmmmmmmm...............

 

 

 

 

 

 

 

 

 

The mower realized that Justin Bieber was riding it and decided to commit suicide.

 

 

 

 

 

 

 

 

 

THE END.

[Ratwagon1600]

That should buff out !

[HRH]

Get a connecting rod and put it back together!

[metalmonkey47]

Get a connecting rod and put it back together!

 

Need a lot more the a connecting rod :poke:

[cdub42]

20 years is like 100 years in lawnmower years. I've never had a lawnmower explode like that tho

[datsunaholic]

My grandmother's 3-year old self-propelled mower chucked the rod out the side of the block.

 

Yet my 7-year old mower with a bent output shaft (I ran over a 4-link suspension arm that was buried in the grass, which bent the output shaft and the mower blade. I pounded both back straight with a sledgehammer) just keeps running.

 

I have a 30 year old Snapper riding mower with the original engine, too. Think it's either a 7.5 or 8.5 HP, but I can't remember. It's so loud I'd never hear a rod knock.

[c10jim]

What's a lawnmower?

[MikeRL411]

What's a lawnmower?

 

A steel and Aluminum replacement for a goat.

[thisismatt]

A B&S engine that lasted 20 years? I call shens

[metalmonkey47]

My grandmother's 3-year old self-propelled mower chucked the rod out the side of the block.

 

Yet my 7-year old mower with a bent output shaft (I ran over a 4-link suspension arm that was buried in the grass, which bent the output shaft and the mower blade. I pounded both back straight with a sledgehammer) just keeps running.

 

I have a 30 year old Snapper riding mower with the original engine, too. Think it's either a 7.5 or 8.5 HP, but I can't remember. It's so loud I'd never hear a rod knock.

 

This one surprisingly didn't even scratch the soft Aluminum case that it was housed in! Maybe that's because the rod was Aluminum? Which would explain why it shattered without bending.

 

A B&S engine that lasted 20 years? I call shens

 

:thumbup: It's the truth! I promise :thumbup:

 

It would have kept going longer if people would stop hitting tree roots/curbs with the blades :ninja:

 

I mean, just look at how CLEAN that engine is inside. The cylinder still had nice even hone marks in it.

Edited September 11, 2012 by metalmonkey47

[HRH]

I bought a brand new mower when moved into the house four years ago. Second mowing I hit concrete and bent the crank. After that I've gone to habitat for humanity for the rest of my mowers. Just put a crank seal and replaced a breather tube in the current mower. Stopped leaking oil and runs a lot better! :D

[jon521]

 

new shift knob?

[flyerdan]

I've got an old mower that I use to mow up leaves in the fall, got it off the IGA shopper (well before the internet) at least 20 years ago and it was old then. Last fall just when I was finishing up the last of the, it broke a rod. Fortunately I had a spare hanging on the wall and the seal and gasket weren't damaged so it didn't cost anything to fix.

[metalmonkey47]

The replacement came in :thumbup: Ordered up and got the 17.5 instead of the 12.5

 

 

 

 

[yellowdatsun]

Some JB weld will fix it just fine.

[I'm BLUE]

I've got an old mower that I use to mow up leaves in the fall, got it off the IGA shopper (well before the internet) at least 20 years ago and it was old then. Last fall just when I was finishing up the last of the, it broke a rod. Fortunately I had a spare hanging on the wall and the seal and gasket weren't damaged so it didn't cost anything to fix.

 

Tecumseh engine ?

[flyerdan]

Nope, a Briggs. One of the 3.5 hp lawnmower engines that they made millions of.