Warranty not honoured

we purchased a used engine from Boston Jap-Tech on 4 Nov 2014. The engine was installed in the vehicle and when started on 3 December 2014, it seized. On 4 December 2014, we took the engine back to Boston Jap Tech to address the issue, however they said that the engine carried no warranty.<br> <br> The engine was purchased as a replacement engine, which is the fundamental principal of the Boston Jap Tech business. They sell engines for replacement use. It is therefore assumed that while the engine is used, it would be of \good working"condition"