When you turn the prop by hand it really is hard to turn over even with no glow plug in it. It feels like oil has congealed around the bearing or on the cylinder wall. There is no scraping or grinding noise -- it is just stiff to turn over. The engine was given to me, I suspect regular oil was used a few years ago when the engine was put up and it just sat there all this time. Is there anyway to clean this out without disassembling the engine? Thanks for any input.