squealing on start up

ANother trick is to use a bar of soap on the belt. WHile it's running hold the soap on the belt grooves and the squeal will stop.

But this method along with belt dressing only lasts til the next rainstorm. Then it washes away.

Either replace the belt, and try putting WD-40 on the pulleys. Also, check the idler pulley, they tend to squeal.