So I recently picked up a trailblazer 250 that has been sitting atleast 8 years. I cleaned the carb and fired right up( got parked because it got wrecked into a tree and busted the left front steering knuckle) it only ran and revved but had very high idle and bogged only sometimes it idle down enough to get it in gear,and it moved!! So I took the carb apart again, and reset float level and throttle cables,So today I started it up and in a few pulls idled perfect!! Alittle revv and Boggs let it run for 2 min and it clears up and runs great!! BUT HERES WHERE IT GETS WIERD I had it hangin at 3500 ish rpm and let off throttle but...it still hanging a 3500 rpm so I turn the runs switch off and nothing!!! NOW UP too 4500 ish rpm and climbing!!! Then turn key and still nothing!!! And then pull spark plug wire ITS STILL RUNNING AT 5000 rpm!!! 30 sec later I start frantically ripping air box off and cover the carb with my hand and finally it shuts down!!! Wheeew So my question is from sitting so long could the cranks seals go bad?? And or what eels could be the problem? Also I haven't tried to start it since.