Excellent engines, they tend to last forever barring a crash or something.
You can soak the carb in raw glow fuel, ethanol, acetone or methanol too. Soaking it down with WD-40 works too. Usually you need to heat the carb up some with a hot air gun or heat shrink tubing gun or even boil the carb some in a small old sauce pan on the stove even. Usually the old castor oil tends to get thick or harden up over time and it makes things stick.