I have an old Dayton Riding mower with an 11hp B&S engine, 5spd, electric. I adjusted the carburetor to 1 turn on the top idle screw and 1 1/2 on the top speed bowl screw. I then adjusted it and got it running good. The problem is when i hit some tough grass the engine boggs. I also can not put the engine at FULL throttle or it will die. What adjustments should i make? Should i run higher octane fuel? Any tips on makin the engine run the best it can?