Hit a stump, now timing is off?

[Virtuoso]

So I was hastily mowing our lot last week, and hit a stump. Stopped the mower dead in it's tracks, and bent the blade

Fearing the worst but hoping for the best, I purchased a Gator blade (works great btw!) and installed. Now it seems to run 95%. It doesn't vibrate like it bent the crank, but it misfires for a short bit when cold started, and will pop once from (generally) the exaust when restarted hot.

Have I bent the crank key just enough to throw off the timing a little perhaps? It's a two year old Craftsman with a 6.75tq Briggs. I have not ripped into a small engine in a long time, but this one should still be worth fixing.

TIA

 

[mechanicx]

It sounds like the flywheel key sheared and the ignition timing is off some. You have the symptons of the timing being off slightly. And based on the shape of that blade it's not too surprising.

 

[Bill in Utah]

Originally Posted By: mechanicx
It sounds like the flywheel key sheared and the ignition timing is off some. You have the symptons of the timing being off slightly. And based on the shape of that blade it's not too surprising.

Agree!

With the blade bent that bad I'm surprised it runs at all!

Bill

 

[CharlieJ]

Originally Posted By: mechanicx
It sounds like the flywheel key sheared and the ignition timing is off some. You have the symptons of the timing being off slightly. And based on the shape of that blade it's not too surprising.



Yep. I had a similar incident happen about a year ago. Take the flywheel off, you most likely just sheared the key. You can get a new key at a mower repair place. I got a new key for $1.

 

[Scienceman]

You hit a large stump. I'm suprised it runs this well!

 

[greenaccord02]

Yeah, just pop that flywheel off and get a fresh key.

 

[lexus114]

Originally Posted By: Bill in Utah
Originally Posted By: mechanicx
It sounds like the flywheel key sheared and the ignition timing is off some. You have the symptons of the timing being off slightly. And based on the shape of that blade it's not too surprising.

Agree!

With the blade bent that bad I'm surprised it runs at all!

Bill


It`s A Briggs.....

Man that blade is Bent!!

 

[Bror Jace]

Let's hear it for blades made from soft, mild steel.

The fact that the blade bent that much might've saved the motor. If it was a hardened tool steel, it would keep its edge better and not wear out as fast ... but when you hit something HARD, it's bye-bye mower (bent crank, broken rod, etc ...).

 

[lexus114]

That`s true,but then again,were not supposed to hit tree stumps/very hard objects.

I`v done it myself too.....

 

[Virtuoso]

I knew it was there too. I guess I figured I was far enough away. I thought I did the motor in, it was quite a stop.

It needed a new blade anyway, but I didn't want to change it out of neccesity like this LOL. The Gator is a heavy blade, I'd imagine the motor may not fare as well if the same mistake is made.

I highly reccomend the blade though, it cuts great. I'll be picking up a new key for the motor later this month and tear into it.

 

[Kestas]

I sheared a key once. The engine would cold start, but I could never get it restarted when warm. It wasn't until I found the sheared key that I understood the problem.

 

[Nick R]

Once, when we first moved to hawaii, first time I mowed our lawn, I didn't go over it. There was a 4" diameter iron drainage pipe sticking out near the edge of the lawn, thick walls, like 2.5mm. I couldn't see it through the tall grass, and ran over it with the ancient, junk mower the people who had previously lived in the condo section left. That thing stopped it good, broke the blade (not just bent). It still ran once we replaced the blade though, I was shocked.

 

[greenaccord02]

I tore up a barbecue grill grate the other day with mine. 4.5 hp briggs with a 21" Gator on it. It tore up the grate and stopped the blade but didn't bend the blade or skew the crank at all.