ORIGINAL: highonambroid
I'm coming back from about 20 plus years away from building and flying RC aircraft. During the hiatus I was able to hang on to one of my planes powered by an OS 40. The prop still turns with a little ''gummy'' feeling but there's still compression. I've pulled the head screws and was able to remove the head/cylendar sleeve and it all looks pretty good other than the carbon deposits on the top of the piston. The throttle is stuck so I think I need to soak it in something to get that free enough to disassemble. What's the best cours of action to get this enging back on line?
Put the whole thing in a ziplock bag (I use freezer bags for soaking parts) and put enough model engine fuel in it to cover the parts. Leave it set for several hours to overnight and it should be loose enough to get everything moving and ready to run. If the bearings feel gritty, you might consider changing them before running it.