How to fix your lawn mower after hitting rock/stump (Briggs/Stratton EX Engine)

Part # 222698

This video shows how to fix your lawnmower after hitting any large objects such as a tree stump, rock or any other material. This repair will fix the flywheel key timing on the Briggs and Stratton EX engine, this principle applies to many other Briggs engines such as Sprint, Quattro, Quantum and Intek series. The cover removal process is more difficult for the older models but the the flywheel key replacement is the same.

Due to factors beyond the control of Alex S “Multikhaz”, it cannot guarantee against unauthorized modifications of this information, or improper use of this information. Alex S “Multikhaz” assumes no liability for property damage or injury incurred as a result of any of the information contained in this video. Alex S “Multikhaz” recommends safe practices when working with power tools, automotive lifts, lifting tools, jack stands, electrical equipment, blunt instruments, chemicals, lubricants, or any other tools or equipment seen or implied in this video. Due to factors beyond the control of Alex S “Multikhaz” no information contained in this video shall create any express or implied warranty or guarantee of any particular result. Any injury, damage or loss that may result from improper use of these tools, equipment, or the information contained in this video is the sole responsibility of the user and not Alex S “Multikhaz”.



39 thoughts on “How to fix your lawn mower after hitting rock/stump (Briggs/Stratton EX Engine)

  1. Briggs & Stratton engines have, for many years been designed so the flywheel key sheers when the engine comes to a sudden stop. It is to minimise damage to the engine and components.

  2. Same engine on toro timemaster just the shaft is longer for twin blades 30 inch deck. Just different problem but good to know for troubleshooting because i had hit stuff before.

    My issue was head gasket blown. I was told to replace an engine for $400. I didn't, i bought the head gasket and replace it that only cost me $10 and 30 min. Now runs like a champ at first pull.

    Thank you ?

  3. Thanks for the video, i was able to replace the key with your video but the lawn mower still not able to pull. Do you have any idea? Just in case, I took out the blade see if there is anything, The blade won't move at all. so does pull wire won't pull at all.
    This is all after hit the metal pipe. Thanks

  4. Thank you for this video. I was about to take my mower to the shop because I knew the timing was off because I hit a rock. But I took it apart and sure enough the key way was sheared off. About to go to my local mower store and get the $3 part to fix it. They were thankful that I had the part number too. Wish all YouTube videos were this informative.

  5. Good video man, thanks – will work for many engines, the key is how you get that flywheel off and on safely without breaking anything else. I'm 99% sure i'm doing this tomorrow after trying to mow a gate hinge with my Stiga….:/

  6. This took me easily ten times longer than it did in the video but then I don't know what I'm doing. The engine still knocks but not as bad, and I can cross one solution off the list. Thanks for posting!

  7. This video really saved me! Thanks so much for posting. You did a great job explaining and showing the process. My mower stopped working after a blade sharpening. Perhaps I didn't tighten down the blade enough and it sheared the flywheel key?? (like when hitting objects while mowing). Regardless, this saved me probably hundreds in repair costs….you know how shops can be. $2.30 part and 30 minutes of my time. Great video! Thanks.

  8. Thanks for this video!
    I am hoping that this is why my old B&S engined roto tiller won't start now. The tines got wound up in an old underground cable and shut the engine down and I haven't been able to restart it but it pulls ok and seems to have some compression but tines don't spin as fast as a lawnmower blade and I fear that there's worse damage like a hole in the piston or cracked ring or something…. I'm gonna check this first, fingers crossed !

  9. I hope this is all that's up with the mower that belongs to the church my brother works for. I was helping him out by doing a bit of grounds work, little did I know there was an old metal fence that had been removed, but there was still some small metal parts sticking out just enough that I did not see them. I hit one now the mower does not pull start it is stuck. and I looked through the gap and it looks like the plate is split. is this possible and could it have damaged anything else. I was doing a good honest job for nothing, just mowing along and then WHAMMM! and it died. now the church grounds has a half a job done, and I feel bad. I think it would have been avoided if I new about the fence. but God works in strange ways. any help would be appreciated ✌

  10. This is one of the most spot-on how to's ever. I had $400 replacement mower in my Lowes cart when my wife forced me to try this. $2.49 later, John Deere (BStrat) working perfectly. Thank you!

  11. It can be seen in your video that mower vibrates quite rapidly. This is caused by crankshaft radial run-out. After such impact you should also straighten crankshaft, can be done in home if you have run out dial and press bench. I once mowed stump and bent crankshaft. Crank radial run-out was about 1,5 mm. After it vibrated all bolts and nuts loose I finally straightened the shaft at work. Machine worked many years after that without problems.. Until it got next stump of course.

  12. we have a used mower at work and it makes a hard metal clank sound when we first turn it on. Not sure if the previous owner hit a stump or rock. Any Ideas? They think its a bent shaft but it runs and it doesnt really vibrate too much. Someone put a new blade on it thinking that would fix it. Any suggestions?

  13. I got the same engine except it is a John Deere but the key was still intact and the crank shaft was bent and we replaced it but it still won'


  15. I can't believe how cheap all this stuff is. What a pile of crap.Everything driven to the lowest common denominator. Very good video by the way. Direct and to the point, no whining or Redneck crap. Good job.

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