as said on the return journey home, the engine ran at once restless, so not round,in the acceleration also loud exhaust noise.In the standing gas he shook himself from time to time lightly, then it was away,in the start of the journey again there??. No tool,so further,it was a modest ride,everytime when I started it seemed to me as if the engine wanted to go out and the exhaust noises louder than normal. Is it not possible to set off,bad acceleration and easy jerking. Arriving at home,I took off the lid,at first glance everything was normal.OK spark plugs changed,started with 1cylinder, looked very consumed, then the 4th cylinder when pulling off the plug I saw a verbrant spot on the plug also in the candle hole a fire place,through the ignition radio? (picture 1).By the way, I mean that it was not really fixed and a bit heavy in the thread. (picture 2) Candle full Oel,where? top everything was dry. After the candle change, and there is no plug on the cat?