Hi,
I have a DLE32 in a 1/4scale Airsail Auster. Look at how you mount the carb. I've turned mine over so that the pump side (assuming the 20 has a Walbro-type carb) is on top. That way I can get at the pump diaphragm through a hatch on top of the cowling, and take it out to soak in gasoline overnight if the engine has been standing for a week or so. My planes are in a heated hangar (aka a laundry room!) and the gas evaporates, the diaphragm dries out and then won't suck gas from the tank. This is a common gasser problem, but easily fixed if you've set up the carb orientation so that you can get at it. Alternatively, slacken the pump cover screw a bit and blow into a tank fill line to force gas into the pump side of the carb. Tighten screw, leave overnight and next day the pump will draw and the engine will start. Simples.
The DLE32 is a very good engine. It puts out black oily crud at first, but now run in is very clean. I bet the 20 is as good.