340 Duster oil looks milky

Get a glass jar and fill it with the oil from the engine. Let it sit a day or three and see what happens. If it has an appreciable amount of water, it will separate with the oil on top. It could be simple assembly lube mixing in with the oil. Fill the glass and let it sit and you'll know for sure without ever having to turn a wrench.
Great I idea and will try that after work, thank you!