i have 1992 yamaha 200 txrq outboard,it has been running good at wot rpm 5200,42mph on 21 foot center console,one time i run the fuel tank to low,(low fuel waring light come on)very next day take it out start missing,and wot rpm at 4400,and miss in and out,but after few hour running it wont miss but still wot is 4400,what cause it,check compression all good,all have spark(use spark plugs checker),but have not check the spark plugs ,can it be trash in carb?what would u look at first?thanks.