the balancer, take a good look at it from the wheel well, take the wheel off. look around the metal to rubber outer edge. if its bad you'll see a good crack around the whole balancer.
take both belts off, fire it up, see if the noise stops. while the belts are off spin all the pulleys by hand, the balancer, grab it with two hand and see if it wiggles side to side or if you can turn it with out the middle part turning too. or turn it back and fourth a bit.
while the belts are off grab the sc pulley, turn it one way, then snap it back the other way, if you feel a click or hear it, the coupler is bad in the snout of the blower.
