Earnest money is money put down to demonstrate your seriousness about buying a home. It must be substantial enough to demonstrate good faith and is usually between 1-5% of the purchase price (though the amount can vary with local customs and conditions). If your offer is accepted, the earnest money becomes part of your down payment or closing costs. If the offer is rejected, your money is returned to you. If you back out of a deal, you must forfeit the entire amount.
Several methods are available for dealing with screws that tend to vibrate loose on covers of equipment such as chainsaws. One good fix is to remove the offending screws and wrap 1/2-in.-wide Teflon tape around the threads and then screw them back in. The tape will hold the screws tight, yet will allow you to remove them when necessary.