Motor hard to start. Have to take callen off and use choke. Idles about 60 seconds, then dies. Cranks right up. Runs great. Fish for about an hour and same staring problems occur. This is the second motor on the smae boat. The other motor was an Evinrude 150, 1988 model. I had the exact same problems with the 'rude. Have had carbs cleaned and adjusted. any suggestions?