I have a problem with my little ( 3,6 )
. When I start it, it runs the first ca. 5-10 seconds normal and then suddenly the speed drops off so that it almost goes off !! At this time he only accepts gas extremely reluctantly (only by pumping with the pedal) and has repeatedly misigned. The combustion is obviously very bad because the exhaust gases stink to the sky which he did not have before. The whole thing lasts about 2-3 minutes, then suddenly he thinks again, is idle, takes on gas and only stinks.
The whole thing is every time it's restarted. Does anyone of you have any idea what this could be??? 
Thank you for your tips and greetings from the "Ratlose"