I have a 25 hp, Kohler Command engine. The engine developed an air pocket and was run about a minute or so without any oil. I fixed the problem and now the engine is hard to start. Meaning: Slow cranking. I put in a new battery and it helps a bit, but it required about 400 or 500 cca to start this thing. Once it starts, it runs fine. I have a few questions: 1) Will the engine smooth out a bit and wear in? 2) Will using synthitic oil help, or perhaps a lower weight oil? I assume the tightness is in the pistons and rings? Anyway to free up the engine - Marvel Mystery Oil? Any Tips?