Are you sure that you are runing only 5% Nitro, with the speed that you are getting it seems that it would be a higher Nitro %, I would run no less then 20%, if you are planing on racing this boat I would run 40 to 50% Nitro fuel, but remember the engine life span is shortened by the higher % of Nitro that you run, but as always consult your owners guide, I checked out the boat on line, it looks like it a really nice boat.