Small Engines (Lawn Mowers, etc.): Lawn mower, hairline fracture, self propelled lawn mower

Question
I hit an object with my self propelled lawn mower and I bent the crankshaft. My local dealer said they can straighten the crankshaft without removing it from the engine. They have a special jig and a press. Is this a good repair? The mower cost about $400.00 and is in excellent shape otherwise. Thanks.

Answer
All engine manufactures highly dis-courage shaft straightening due to liablity issue.

Our shop will not straighten shafts for the same reasons.  Once a shaft is bent the structrual interity is compramised.  It's possible that the shaft may have a hairline fracture which could cause the shaft to break under pressure.  The worst case sceniero is the shaft could break and cause severe injuries to your lowers legs if the blade or shaft was to hit this area.  For this reason most shop do not straighten shafts.

I have straightened my own personal shafts before but the equipment is never the same.  It is pretty much impossible to get the shaft exactly straight as the orginal.  Usually the mower will vibrate slightly more than before the shaft was bent.

I have never actually saw a shaft break but have seen some pictures where they have and caused severe leg damage to the operator.

I would use your good judgement now that you know the risk associated with straightening the shaft.

I hope this helps.
Eric