sticky clutch need some help...!!

hey, i have a rmk 900 159' , my clutch wants to stick when its engaged and not desengage witch causes it to kill the motor if i have the brake on,. and when i start it and left worm up and then ready to take off it revs up to like 4 and then boom takes off and then ideals way down read away and dont want to desengage. i have 10 78 weights in it now i had 10 72 when i bought it .. i didnt change the spring tho its black. when i bought the 10 78 weights they said that spring would work .. i just bought the sled two weeks ago. i used to ride ALL skidoo , but rode my rmk and loved it ... but hope i am making a good decsion :face-icon-small-dis..?? i leave for the big horns on the 18th and going to show some skidoos up ..haha :face-icon-small-hap i need some help guys .. THANKS ..

thanks guys .. i put the 10 72 back in and it dont do it as much .. but who do i take it to have it looked through and balanced ?? and how much dose it coast for that ? one other question is i can only go 65 mph at about 7000 rmp.. is that normal or do i have a low gear? :face-icon-small-dis