my 23 kawi on my bobcat Z rider will blow white smoke when I fire it up for the first time of the day. A couple times a week it will do it when I fire up the mower after its been parked on a slight hill for a couple of minutes. The oil,air filter, fuel filters have been kept up more often then the manual advises for so I would hope its not pre-mature engine wear/ring wear? Would it be bad valve seats? Oil level is just about spot on maybe a hair above level. 900hrs. on the engine. The white smoke smells like burnt oil so I know its not fuel.