I'm necrobumping this thread... Got this old girl from a fellow clearing an engine collection he purchased from a collector. Among the engines in the box were a Max-H .40, Max .25, Max .15III, LA .25, FSR .25 (I found a NOS piston/liner for it), .60FSR, .46FX (2, one had a peeled liner), and a few other engines (there were at least 16-18 in total). I'm in the process of refurbishing this .15III. It appeared someone crockpotted the engine in antifreeze too hot and greyed the case and muffler. I was able to clean up the exterior and interior and reassemble with a new cylinder gasket. The engine needs a thrust washer (it was run for some time without one!!), but is otherwise complete and in operating condition. The muffler looks worse than it is, but I'm cleaning it up. My thoughts were to use a 8x3 or 7x5 prop to test run it, short idle bar plug (I have several to use up), 12% nitro/23% castor fuel, and a small 2oz tank using muffler pressure. It seems what has been said about these engines is they liked to rev, but if revved up past 15,000rpm they won't last long. If this engine survives the test running and runs nice enough, I may try using it in a small 1/2a Norvel trainer for kicks. I used LA Totally Awesome on the engine and a combination of the LA cleaner and Bar Keepers Friend kitchen cleanser. It seems to be a good alternative to the Dawn Power Dissolver that is almost gone.