Small Engines (Lawn Mowers, etc.): Looked Like Oil to me, cam gear, model numbers

Question
I added what I thought was oil to my lawn mower (sounds stupid, I know). What ever it was it caused the valves to stick after it cooled down.  I pulled the engine down and cleaned everything up but... Now when I start the engine it runs at excessive rpms for about 30 seconds, and shuts down as if it runs out of gas.  After 8 to 10 pulls (little hard to start) it will start and runs fine and easily restarts, but may backfire when shuts down. When I reassembled the engine I didn't know if there was a particular starting position of the crank to the valves.  Basically I just placed the crank to a position where both valve were closed.  Have any suggestions?

Answer
 Hello Mark:

 Did you Not Line up the Timing Marks on the Crankshaft and Cam? There is a Mark on the Crankshaft Gear and the Cam Gear that Must be Lined up with each Other to Set the Valves. It Sounds like the Governor inside the Engine is Sticking when you First Start the Engine. Send me the Model Numbers Off Of the Engine, Please. With these Numbers I May be Able to Locate a Breakdown of the Engine and Better Assist you. Hope this Helps. I am here if you Require more Assistance. Let me know what Happens, Please. Thanks.

 Good Luck

 Respectfully

 John