My cox 0.49 medallion

Welcome to CEF, Tom!

My name is Jim, and I'm a Coxoholic. I've been addicted.to.th3se engines since childhood, and still have a few from way back then.

Bob has served you well. His perspective is saving you effort and provides a piece worth showing off, and will provide a quick, easy way to run it. I find no fault in his advice.

I love these little engines too. But I'm primarily a function over form kind of guy. So my answer is from a "I want it running" mentality. In other words "no knock on my friend's advice."

Alibi alibi, alibi:
I'm also bad about over-analyzing stuff. Really!

I would do a quick external dry cleanup (old toothbrush works) provided the piston is high in the travel and blocking the exhaust ports without exposing the SPI...that is, the exhaust port gap below the piston (if any). Then, once dry brushing the abrasive crap away, I would disassemble as much as possible. I would NOT consider using a dry-rotted plastic "front case," as they are readily available from Exmodelengines, Cox International, and MECOA. The rest can be cleaned in pieces and reassembled with a fresh plastic front end. For any sticky parts, heat is your friend...but it will ruin that white-ash front end. If you cause no damage removing the front end, then by all means, test run with that bleached plastic...but be prepared to let it go.

All the parts will be better cleaned in parts than whole. This isn't like disassembling a Honda DOHC 6 cylinder CBX engine (many, many fewer parts in the Cox engine). The trick is to clean it enough so no damage is incurred as it is disassenbled. The more you take apart, the more you can target the filth and target lube. Once the delicate plastic part is removed, you can use Berryman's or Fantastic 409 to really clean the metal parts. Wash and dry anything that water touched...period..Even 70% rubbing alcohol will.remove a significant amount of water if you don't have a compressor. Oil all parts with light machine oil or castor oil as you reassemble. Your fuel will oil everything as you run it. Store it oiled using any available light oil so nothing rots until next use. Even a few drops of automatic transmission fluid (ATF) will be better than nothing...or air tool oil...or 3-in-1 oil...just something light that doesn't gum up until next run.

The ball joint under the piston is a place I would carefully check, as well as front case bushing wear (where the crank rides) and piston-to-cylinder slop. The glowhead can be checked once clean, and "bubbled clean" with some good old fashioned alcohol to clean, and then a D cell battery to burn off the alcohol and junk. Watch out that you don't burn your fingers! Once all parts are clean, then reassemble and perform "break-in," just because you never know what you have until it is running. A 5x3 prop will be good. Run rich at first, then lean out as you learn the engine.

Who cares if cleaning etches the black off the cylinder (I don't)...that can be fixed later IF the engine is worth the extra effort (another cleaning cycle). Bob can speak on using blueing chemicals much better than I can. He really does a fantastic job reconditioning model engines.

So, in short, you now have the two extremes recommended. I strongly suspect your solution will fall cleanly (hahaha) in the middle.

Enjoy the toy!

PS...the engine manual is in the INFO section, just below "Latest Topics." It will give you good guidance too.