2 days ago the engine was running fine during warm-up (it is on a firewood processor). After about 10 minutes at running at half throttle is shut down. Now it will only run at idle. Oil has been changed and is to the correct level. Gas comes from the drain valve and is fresh. Air filter is fine and it does this even if the filter is off. Spark plug is gapped correctly, sparks fine and gets wet is the plug wire is pulled and the engine turned over. Pulled the float bowl and cleaned. It looked fine and reinstalled but it still does this. Cannot find any external screws to adjust. Am at a total loss. Any help is appreciated.

Audio Players & Recorders - Technics - SA-EX400 Receiver