ORIGINAL: dwilt72
ORIGINAL: bigedmustafa
The .40 LA would benefit from added castor oil. It will run OK with 80/20 synthetic castor blended lubrication, but extra castor oil would help float the crank shaft inside the bushings and the engine will actually produce slightly better compression and more power with an all castor lubrication package.
The ideal fuel for a 2-stroke with bushings instead of ball bearings is 10% to 15% Nitro and 20% pure castor oil for lubrication. Folks who don't like the O.S. Max LA series have probably never tried running them with the proper fuel. This mix is also recommended for the Thunder Tiger GP series and K&B Sportster series of glow engines.
The Kangke SK .50A should be a little more flexible with regard to lubrication, and should run fine on most any sport fuel that meets the manufacturer's recommendations for basic nitro range and minimum oil content.
Does this also apply to the OS .46 LA?
The OS 46 LA is the same engine as the LA 40 - only with a slightly larger piston/cylinder bore. Yes, any bushed ABC or ABN (such as the LA series) should be run on 10%-15% nitro and at least 20% oil. The oil should be a 50/50 mix of castor and synthetic although all castor would protect the motor better. All synthetic is probably not recommended. The engine will run on it but won't last very long.