Engine BS Vanguard 613177 type 0114-e1 code 5122612. This unit has about 1000hours, first time to check valve clearance. How can the clearance be zero or less on the exhaust on one side? I checked and double checked to be sure the valve stem was in the saddle on both ends. The other 3 clearances ran .006 - .011. I readjust all to .006" and the Unit started and ran but I shut it down thinking I may missed something.