So this is what a broken flywheel key is like...

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Mower started badly today but I did manage to do half my lawn then suddenly putputput and it died.

I had fuel, spark and compression so lastly timing...I did not hesitate, drained the fuel tank, took of the cover and looked at the flywheel.

Now i need to find a new 3x5mm key.

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Mower King

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Mower started badly today but I did manage to do half my lawn then suddenly putputput and it died.

I had fuel, spark and compression so lastly timing...I did not hesitate, drained the fuel tank, took of the cover and looked at the flywheel.

Now i need to find a new 3x5mm key.

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Yep, that is a sheared key, just make sure you replace it with an Alum key & not Steel!
 

Hammermechanicman

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Why is that. my other briggs v-twin has a steel replacement.
I think this is steel also. i found 2 replacement but no stats on them.
 

Mower King

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Why is that. my other briggs v-twin has a steel replacement.
I think this is steel also. i found 2 replacement but no stats on them.
If it sticks to a magnet, it's steel,if not, it's Alum. People have this misconception that the flywheel key holds the flywheel from turning / spinning on the crankshaft.
 

Hammermechanicman

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You can use a big screwdriver wedged in the starter ring gear and a solid part of the engine. Impact wrench. Strap wrench on flywheel. Remove spark plug and insert some rope/cord into the cylinder. Rorate engine till piston contact cord as a piston stop.
 

Mower King

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You can use a big screwdriver wedged in the starter ring gear and a solid part of the engine. Impact wrench. Strap wrench on flywheel. Remove spark plug and insert some rope/cord into the cylinder. Rorate engine till piston contact cord as a piston stop.
If you use the rope trick, make sure both valves are closed at TDC or you could bend a valve. I personally like the Impact but, you do have to know your Impact or....other problems might occur!
 

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should i torque it or a one good elbow twist enough, it came lose very easily before ...
 

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If it sticks to a magnet, it's steel,if not, it's Alum. People have this misconception that the flywheel key holds the flywheel from turning / spinning on the crankshaft.
its tapered shaft so its the friction of the 2 bodies that keep it together i guess. much like the 50ton overhead crane wheels at work. iv seen them come loose by itself and some even broke off.
 
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