I guy I work with has a never been used, still in the box, royal .40 engine. He asked if I wanted to buy it. Is it worth anything? I havent been able to find much info on it. Any advice would be appreciated. Apparently, he was gonna get into the hobby 20 years ago, bought some stuff, and never did anything with it.

I have the .45, and as far as I know pretty much anything made in the 90's was Schnuerle ported. Mine runs great, but is not going to be as strong as the modern engines. It will pull a 40 sized trainer, but you will not have a lot of excess power. I would avoid using it off of grass. The .45 turns a 10x6 prop well, but the newer .45's will turn an 11 or 12 at about the same RPM's. As long as you have a plane that will be able to use it it should be fine as long as it is in decent shape. Biggest thing is you should not be able to hear or feel the bearings when you turn it over.

I have a couple of them and they are great engines.
They are bearinged so more powerful than my 40LA.
May be more powerful than my 46 LA.
They are not considered valuable or collector items.
Buy it for about $30 to $40. If you don't want it, I do.
Good Luck,
KW_Counter

The only thing I found wrong with them is the carb would break the front case in a crash[:@] Other than that great little engines for there time.

As I recall, the Royal .40 & .45 were copies of the OS .40FSR and .45FSR. I did know fliers who used Royal .45 cylinder and piston sets to replace the more expensive OS parts. They were a drop-in fit.

The actual Royal engines tended to have lower quality parts, but ran well if you got a good one.

Since the FSR series of engines, OS has gone through the SF series, the FX series and is now into the AX series. This indicates they are an old design. I would offer $20 for the engine. You may need to replace the bearings after all this time and all the rubber O-rings. Once it is de-sludged, it should run fine. You should be able to use Royal or OS FSR parts. You might be able to find them on E-Bay. I'd check RC Bearings for those.

A 10-6 prop is the correct size and I'd use 10%-15% fuel. Since it is an ABC type, don't run it in a rich 4-cycle, use short 2-cycle runs for break-in.