hayter harrier did this! what happened!!? briggs and stratton

[rispodium]

hi,

i was mowing and suddenly there was a bang and i looked underneath and the blade
and the plate under it had come off the mower and the bolt that held the blade had
sheared right off. What has caused this? its like the shaft that turns the blade has been
under pressure

there was nothing i could see grapping or resricting the blade
it was only small grass.

could it be the oil or something? Im stuck really.
the part that snapped is the "blade boss" .

dunno what to do next...
please help,

thanks

from Dave.

PS anyone tried stp oil to improve compression?

 

[ILENGINE]

Most likely cause is hitting a stationary object. But maybe the blade bolt was overtorqued and cracked under load.

I have seen STP in the incorrect ratio turn to the consistency of grease in a Kohler Command horizontal.

 

[bertsmobile1]

As you mow the action of the grass under the mower tends to tighten the blade bolts.
This is intentional.
You only need a tiny rust pit to act as a trigger and the bolt will break
This is why the manuals tell you to replace these bolts at regular intervals that no one ever does

 

[pugaltitude]

Hayter Harriers usually use a friction disc which allow the blade to spin if hit against something hard but not tighten the bolt.
Hayter also give crankshaft a lifetime warranty if you are the original owner.

Take it to a hayter dealer.

 

[Tinkerer200]

I don't know anything about that brand of machine but another possibility is - all power mowers of recent vintage are required to have a blade brake designed to stop the blade in (?) seconds. IF you don't get the blade mounting bolt tight enough, when the blade brake goes on it may unscrew the blade mounting bolt to where the blade slips when restarted eventually wearing the bolt in two.

Walt Conner