I went out on a friend's boat 2 weeks ago. Running a 90 HP 2 stroke Yamaha (don't know the year)...temps were in the 60's...the motor ran fabulous...like a new motor. This past weekend we went out again...it was cold and windy...temps in the mid- 30's...the motor ran TERRIBLE...really rough, coughing, sneezing, stalling. I couldn't believe the difference in how the motor ran just because it was cold. Is this normal? My friend says it happens all the time when it's cold...he usually quits boating when the temps get below 40 degrees.