someone gave me an older rear propelled, lawn boy gold series,3speed,2cycle because they could not get it running. I changed the plug and fuel mix and have been using it for the last 9 years. This is the best mower I have ever used. Recently I took off the blade,sharpened it,reinstalled it.started it and about 10 minutes later it just stopped running.It seemed like the spark was a little weak so i changed the pick up coil. It has spark and fuel but it seems not to rotate as freely as it should. I can't get it started again.I really like this mower but just can't figure it out.Anyone else have a problem like this? It usually starts on one easy pull thanks, stevie