[John DiMartino]

There is nothing wrong with letting your 25 idle for 30 seconds before you shut it off.The fan may turn slower at idle-but the engine isnt generating hardly any heat either with no load,and idle speed,friction is low,as is fuel usage which keeps combustion temps down,and My 25 is not a Command pro-the pro is the only one with the fuel shutoff-if you dont have a pro-you should be idling down before shutting it off.If you dont and let it wind out,the exhaust is hot at wide open,you shut if off,the governor is mechanical,it opens the throttle blades and dumps fuel into the engine,the fuel goes thru the motor and blows up in the muffler which superheats after shutdown.I feel the problem with Bassman's is the carb leaking down,either from a high float level,leaky needle/seat or loose bolts,gaskets.The motor is running rich when its blowing black smole-this is no good for it at all,and washes the cyl down,and dilutes the oil with fuel.The easiest thing to do it buy a new carb and bolt it on.