First, does your snowblower also use synthetic oil? My guess is that it does. That would mean that the bearings, valve guides, and cylinder walls are lubricated within the first few seconds. With petroleum-based oils. The oil did not flow until it had heated up.
Second, I believe these carbureted engines have a restriction choke. Effectively, the choke is acting like a closed throttle.
Third, the initial priming made a fuel rich mixture. The extra air from a wide-open throttle compared to having both throttle and the choke closed helps to consume that fuel.
This message was modified Oct 9, 2010 by DavidNJ