i need help. my dad has an 06 yamaha 25hp. with low hours and it keeps poping through the exhaust, and is difficult to idle when slowing down. my dad took it to the shop once before to get it fixed and the mechanics said it was the carbs that were causing the problem. so he paid them to go through the carbs... that didnt fix the problem. what else could be causing the problem?? it only started doing this after he let it sit up during the winter. it has brand new gas, and clean plugs. i even went back through the carbs just to make sure the mechanics did what they were paid to do. im a car guy, so i dont know much about boat motors. please help.
