Small Engines (Lawn Mowers, etc.): 22HP Briggs power loss, briggs and stratton, engine vibration

Question
Hi, i have a Craftsman 22hp OHV I/C Platium briggs and stratton(model # 407777,type 0-174 EI) lawn tractor. When ever you rev it up all the way or Put the forward pedal down for max speed or put the tractor under little load when snow blowing it loses power and blows black smoke. the carb is clean , new plugs and changed the air filter.. Please help...

Answer
Joe

Carb problem is very likely. first thing to do is see if it's adjusted properly - if it's adjustable, newer carbs usually aren't. Pay special attention to the idle screw, is it still in place? Sometimes engine vibration cause them to fall off or eject when spring loaded which usually results in high-rev idling. If adjusment doesn't solve the problem or if the carb is not adjustable (Welch plug instead of screw) you'll have to take it apart and check the float assembly, the float needle may have become unseated