alright.i have just bought me a 98 yamaha waverunner xl1200.i used to have a sea doo xp1000 which was fast.now this yamaha doesnt seem as fast.its off the mark is not good and slight misfire so think needs new plugs,but just wondering what speed should this do,it was doing roughly 80km/h is this right or should it be faster?what is the common faults with these skis?what should i look out for?