I took apart an OS 61 SF last night to check its bearings, since it was somewhat hard to turn over and hadn't been run for a long time. As it turned out, the bearings look ok. The problem appears to be that the con rod is frozen to the wrist pin in the cylinder. This is what makes it hard to turn over. Also, I can't get the piston and rod out since after removing the liner I can't move the rod back far enough to get it off the crankshaft. Again, it appears to be a problem it the upper end where the rod won't slide on the wrist pin. Running it might loosen this up or it might destroy the piston, so I am hesitant to do this. Have any of you ever encountered this problem and, if so, do you have a fix for it?

Jeff

Take the back plate and carb off and drop it in a jar of fuel. That should loosen up the crud everywhere. You could probably even squirt some fuel up into the wrist pin area and let it soak upside down so the piston hold fuel like a little cup, thereby soaking the wrist pin. If you have a micro butane torch, pull the head off and heat the top of the piston, it will prob heat the wrist pin up enough to unstick the oil thats in it.
Put the whole engine in the oven, minus the carb at about 150-200 degrees for 10-15 minutes.

I destoryed an Enya 61 by using a torch to heat it up. After that I learned that you can put it in a pot of boiling water to loosen up everthing. Might boil out the oil, but this could be repalced. Just my two cents worth, whch sometime is not even worth a penny. good Luck
Fred

You do have to be careful with a full sized propane torch, but a micro butane torch would take FOREVER to hurt anything since all of the aluminum inside the engine would be acting like a giant heat sink.

Jeff:
Remove head and backplate, drop it in some boiling water. Hold there for say 3-5 minutes to boil off whatever is holding it in place. I had same problem with ST 61.

Orlando

Thanks, everyone, for the various tips. Some penetrating oil, a monokote heat gun, and gobs of patience got the job done. The engine is back together and turns freely once again.

Jeff