recently purchased a 84 searay 268 with 510 hrs.engine rebuilt 2 years ago...while throttle wide open.feels its going slow.mph wont go over 10...if it register at all..yestedy white smoke came from engine across the lake.boat cut off . crunk it back on..no responce from the throttle..you can hear the engine running but no responce from the proppeler blade....finally responded.alittle above idle.but that was all the throttle i could give ..it...what the hell is going on... 