I hit a concrete stepping stone with my riding mower and now the blades won't stay engaged. How do I fix?

Question

The mower is an old Yard man 42" riding mower. The impact locked up the blades and killed the engine. After I pulled the stone out, the engine restarted. When I engaged the blades again, they came back on and were cutting grass but I'm guessing at a much slower speed because they hardly made any noise at all and when I got into some taller grass, the blades seemed to disengage altogether. I haven't checked yet but obviously there's a good chance the blades are bent. What else do I check? I read something about a key that could have sheared....but if that were the case, I'm guessing the blades wouldn't engage at all. Any suggestions on what I should be looking for? Thanks.

Answer 1

I hit a tire iron in tall grass I missed and did not see one time. The blade got bent and would not stay engaged in tall grass. replace blades first then if still does it you may have done something to the shaft. if new blades don't work take it to a lawn mower shop.

Answer 2

I agree that the blades may be damaged and should be inspected before more use.  The other thing is when the blades are stopped in this manner there is tremendous strain on the belt and other components like the pulley and assembly that engages the blades.  You could have bent some of that.  Now the belt could be slipping and not turning the blades as fast.  If the pulley assembly is bent it could also cause it to not stay engaged.  Sounds like you need to remove the deck and do some inspections.

Answer 3

Your guess is most likely accurate.  You sheared off the locking key that holds the blades to the motor crankshaft and possibly bent the blades.  Hopefully that's all the damage you did.  When you remove the blades from the mower drive shaft you will see the key, half of which will be left in the crankshaft and the other half will be in the collar the blades attach to.  Replace it and re-attach the blade assembly, you should be fine.  If it vibrates too much, replace the blades also.