Sep 2011 was mowing and ran over a dusty area and mower stalled, took it in to John Deere who did a complete service and cleaned the carburator. Used it the day it was serviced with no problems. Used it again this past week picking up leaves with grass catcher attached, started just fine, picked up leaves for about 10-15 mins then stalled. Would start again (no problem), start picking up leaves again for maybe 2 mins and stall. Each time would start with no problems. Even tried it without the grass catcher with same results. Read on some other forums that the hole in your gas cap could be stopped up causing the problem but my gas cap says "Not vented" (no hole). I hate to take it back to JD they are so expensive, any ideas ? Has a Kawaski engine if that helps.