shear pin troubles

[mga]

i have a 5hp briggs that i'm trying to get running. when i was checking the coil for spark, i removed the fly wheel and put a 1/2" drill on the shaft to turn it over. it turned over very easy, of course, and there was no restriction.

when i replace the flywheel and recoil, it will start, but the shear pin fails and it stalls out. i have replaced 3 shear pins so far and can't find the problem. there is not resistance on the drive shaft to create any counter force.

so.....why do they keep failing? should i use a steel one?

thanks for any help.

 

[Hent]

Check the torque on the flywheel nut. Make sure its properly tightened.

 

[mga]

thanks.

i'll make sure the recoil clutch is very tight and try it again.

 

[TUBBUGS]

Check the base of the flywheel where it hits the seal boss on the block. I've had them where no matter how tight you get the clutch housing, the taper in the flywheel is worn out a little and you can't get it tight to the crank. You'll be able to run it no load longer than load but it will shear the key every time. Had an old Briggs B from a David Bradley that did that. Figured it out and got almost $300 on E-bay for it! Had several others, especially Briggs 8hp's do this as well.

 

[mga]

after shearing a few pins, i found out you really have to crank down on the coil clutch to get the fly wheel tight. i don't own the tools to do it, but the guy at a local shop did it for me. he had both the fly wheel wrench and the clutch wrench and said they had to be something like 400 inch pounds(?)

anyways...it has worked perfectly since.