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blade mangle/no start


bubba2's Avatar
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08-12-05, 07:32 AM   #1  
blade mangle/no start

i struck a culvert pipe with my 6.5 craftsman push mower. after removing my mangled blade the mower will not start. where do i begin?

 
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08-12-05, 04:54 PM   #2  
bubba2,

You most likely sheared your flywheel key. If your mower was running well before, this should be the place to look. You will need a flywheel puller and a new (correct) shear key.

Remove the flywheel cover and flywheel. If the key is sheared you will be able to see it once the flywheel is removed. Replace the key with a new one. This should fix your problem.

God Bless,
Dave237

 
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08-12-05, 05:42 PM   #3  
Azis
You could try replacing the blade first as you will need to any way. If you are trying to start this engine without a blade attatched, it will not run. The flywheel is not counterweighted and uses the blade as such.
You still may have sheared the flywheel key as well, but you will not damage any thing further by attempting to start it after replacing the blade.

 
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08-12-05, 07:26 PM   #4  
many thanks to both of you.will try asap.
God bless,
bubba2

 
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08-12-05, 08:51 PM   #5  
That's odd, Azis, I've been starting them without a blade for a lot of years. They are hard to idle, but will run without the blade.
Mike

 
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08-13-05, 10:18 AM   #6  
Azis
Posted By: mla2ofus That's odd, Azis, I've been starting them without a blade for a lot of years. They are hard to idle, but will run without the blade.
Mike
Some of the older engines have counterweighted flywheels. He did not mention his model of engine however I see craftsman pushmowers quite often with 6.5hp briggs, I did assume his would be the same and this model has a cheezy ( no offense cheese) flywheel that requires the blade be attatched to counter the piston for compresion and power strokes. Its possible if the engine fires with no counterweight, to cause internal damage.

 
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08-14-05, 12:49 AM   #7  
Quote: ...this model has a cheezy ( no offense cheese) flywheel ...

LOL, no offense. You're right, they can cause internal damage, not to mention broken fingers and a bad bruise at the least if it does kick back once it's running IF it is a briggs with the old one way cranking ratchet on to of the engine (which the one in discussion has not). I've had them kick back and pop the pull handle right off the rope and send it shooting off like a bullet. One hit me in the hip and I'm not sure how long I winced and held my breath waiting for the pain to go away. That was a long long time ago, and it was how I learned NOT to start engines without a blade .


"Who is John Galt?" - Ayn Rand (Atlas Shrugged)

God bless!

 
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08-14-05, 05:41 PM   #8  
it's interesting you mentioned flyback. the pull cord struck my hand bursting a blood vessel. it will be awhile before i can even work on it.

 
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08-14-05, 10:33 PM   #9  
Wow. If the new blade was on and tight when this happened, then the flywheel key is definitely sheared. This is not a hard repair to do, and when you get to it we'll be here if you need any help. Hope your hand gets better quickly!


"Who is John Galt?" - Ayn Rand (Atlas Shrugged)

God bless!

 
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08-15-05, 08:42 AM   #10  
Don't forget to torque the flywheel nut/clutch to proper specs or you will be replacing another key quickly.

 
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08-15-05, 09:53 AM   #11  
Not to thread hi-jack but I just wanted to clarify something...If I pull on the starter cord and the gremlins inside the engine pull back, then that means that the flywheel keys are sheared? I have an old mower that someone gave me that doesn't start and it yanks back like a son of a gun...

 
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08-15-05, 10:06 AM   #12  
Azis
That is the most likely cause. Basically it advances the timing to where the engine fires well before TDC.
Look under the deck of the mower and if there are any signs of significant damage, good chance the key is sheared, as it is supposed to do.
It is a fairly simple repair but does require some mechanical ability when it comes to removing the flywheel. Care must be taken not to damage the fins and the flywheel itself. The coil is also in proximity of the flywheel and can be removed or left intact if care is taken. Air gap should be checked or reset as required.

 
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