I had a Yamaha 200 a few years back, From the day I got it, it was "Cold Natured" even in summer. linkage on the carbs that open and close the butterflies was off a little, so I had that fixed, as well as a rebuild on the carbs. but it still didn't want to start very easily, mind you this is new power head. Anyway, I never got it sorted out completely. In fact, for a year or so, I had to take the cowling off and spray starter fluid into the carbs just to start the pig. Anyway, Devil's horse is right, you want to make sure the motor is trimmed down at least level to make sure the fuel doesn't have to fight gravity to get to the motor. I now have a 95 Evinrude 225, and it seems whenever I have trouble starting it, all I usually need to do is remember to pump up the bulb a little or make sure the motor is down enough. Good luck with it!