Engine Vibrations


Old 07-28-03, 05:26 AM
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Join Date: Mar 2002
Location: illinois
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Lawn mower shakes a bit... bent shaft??

I recently bought a used gas lawn mower... 2 cycle 4HP 22' cut.

It seems to vibrate and shake a bit... whats the best way to tell if the shaft is bad? Thanks!
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Old 07-28-03, 05:27 AM
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If you take the blade off and run it is it better? If so, the blade might be bent.
Old 07-28-03, 06:39 AM
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Do Not take the blade off and attempt to run the engine. The blade is the flywheel for the engine. Damage can and often does happen.

This applies to engines that are vertical shafts. These types are used on rotary mowers. Most will not even start up but if they did the internal damage can occur.

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Old 07-28-03, 06:23 PM
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Correct, damage and or injury can result. Look at the mower from the underside. With the spark plug removed, rotate the blade around while watching it and see if the crankshaft seems to wobble from side to side when turning. If so, it is bent. Make sure the blade isn't bent, that can cause vibration too.

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