I need to refresh my memory on how to drain it, but the oil to use is the same as what is used in the engine. You also need to check the breather for the governor and put a DROP or TWO in the gobernot to keep the diaphram soft. Also make sure that the butterfly in the intake is free and maybe squirt a litte spray lube  on the shaft bushings. Neat little tractors Send me a P-M and include a phone number and we can talk some more.