I have a scag wb with the Kohler engine found here... http://www.kohlerengines.com/onlinecatalog/productDetail.htm?productNumber=Command PRO CV493 I recently put a new silicone seal on the valve cover to fix an oil leak. Since then, the engine seems to have lost power. If I open up the throttle, it will take longer than usual for the engine to get to full throttle, it also takes the engine longer than normal to recover from me putting the throttle past full and onto choke, and then back down. Then engine will now die after a few seconds after what use to be a normal idle speed. It has so little power that it will take 10-15 seconds for the new high-lift blades to get up to speed while the engine is at full throttle I recently changed the oil and the problem seemed to be fixed with the oil change (engine idled fine, blades went fine, etc), but I started the mower today and it's back, here's what the manual says... Engine Loses Power 1. Low crankcase oil level. It's hard to tell the level with new oil so I'm not sure if this is the issue 2. High crankcase oil level. 3. Dirty air cleaner element. Nope, air filter's clean 4. Dirt or water in the fuel system. 5. Excessive engine load. Even when the Engine has no load it still struggles 6. Engine overheated. Nope, even when the engine is just started it has issues. 7. Faulty spark plug. 8. Low compression. 9. Exhaust restriction I did have to remove the muffler for the valve cover seal replacement, so this could be the cause Anybody know what could be the issues here?