I have a mercury 135hp outboard on a sea ray seville. I use it mainly for skiing. 2 years ago the engine over heated and many new parts were obviously fitted. Since then I have struggled to get top end performance and will not get past 3500 -4000 rpm. When being pulled it struggles to pull me up and then the throttle must be fully down to reach a speed which is ski-able. Occasionaly (once/twice a season)I get massive rpm 5500+ at 3/4 throttle, possibly due to no mixture occuring and getting just fuel. Occasionly the performance will increase for maybe 2/3 outings and then drops off again. I have just recently replaced the carbs. It has been suggested that the coils may be bad, or that the carbs need re-setting. I'm losing paitence time and money with this motor. Any suggetions please? tc1topcat@hotmail.com