Hi all:<br /><br />This is a strange one. I use the 9.9 4 stroke Yamaha to push my sailboat. <br />Symptoms:<br />- it starts great and idles well<br />- will initially run up to full power<br />- after running approx. 10, 15 minutes develops amiss, similar to quenching a spark plug, needs to be turned down to an idle, any attempt to give more power results in what sounds like running on one cylinder.<br />- after fussing for 5, 10 minutes it catches and then will run cleanly at all power settings for hours<br />- any suggestions are welcomed<br />Thanks so much!<br />Paul