The x758 I bought last year has 100 hours on it now. All last summer, all winter, and this spring until two days ago it has always started up right away, with very little smoking. Same starting response whether it had run a day ago, an hour ago, or three weeks ago. The last two days though it is having a very different situation happening. At cold start it will crank and crank and spit out thick smoke as it is doing so. After turning over for what seems like quite a while (long enough I've stopped cranking to give the starter a brief rest, maybe 5-7 seconds) then it will fire up and be normal. As soon as it fires the smoke goes away. Subsequent warm starts are fast like it used to be.
Prior to these last two days I've started it up multiple times a week this spring and it has been normal. Though the fuel in it is from a few months back I find it hard to believe that old fuel is an issue that just pops up one day after working fine a few days before. The battery is strong and it cranks fast all the time. Only recent maintenance to it has been to remove the snowblower and install the mower, as well as greasing all lube points.
Any thoughts what it might be?