Is it unlawful to stop payment on a check made for a legitimate "as is" transaction?

Question Details:

I sold a garden tiller. We both signed a contract said that the tiller was sold "as is." The buyer paid by check. The day after the sale, the buyer called me to say that the tiller had stopped working and asked that I take it back. The buyer put a stop payment on the check. Other than taking the buyer to small claims to collect the sale price in the contract, are there other legal remedies? Can the buyer be held liable for damages other than the sale price in the contract? Important Notice