Went to change the oil on an atv that hasn't been ran in a really long time after checking the starter and compression that seemed fine. The oil is so thick only a little come out and I can see down on there it is thick and pasty. Can you clean it out without taking everything apart? I'm down to frame and motor. Carb is off but I'm unfamiliar with the insides of a small engine.
You may want to pour stoddard sovent or #1 diesel through the crankcase to remove the tar. Make sure you get rid of that crap before you run that engine. If you can’t get it out with the above cleaners, you will need to tear it down.