There is no need to clean the throttle with a wet towel.

The engine is out of cylinders, that is, one or more cylinders are not working. It didn't appear until it rained. It should be caused by high voltage leakage caused by damp or damp in the high voltage ignition part. Open the cover and check whether there is water on the high-voltage line, ignition coil and spark plug. If there is, just dry it with a rag, preferably with a hair dryer. If it is leakage, you can see a blue arc at the leakage part after starting, accompanied by a crackling discharge sound.