The Bukh engine in my Westerly is hard to start from cold - by which I mean it takes 20/30 seconds of keeping the key turned to get it to chug into life. After the first start it springs into life at the first turn of the key and runs perfectly. It did this last year; it has since been extensively serviced, but is just the same. So - is it me? Is there a best technique for starting an engine from cold?