I pulled the spark plug and found metal sliver arcing out the plug which fixed only part of the problem. I replaced the plug, flushed the fuel tank, checked fuel supply, removed, fixed and replaced bowl, problem still bugging me. Put everything back together and tried again. The obvious fix was fixing the bowl and inserting the plug very carefully, stop when fuel dripping has stopped bypassing the plug. It prevented the fuel level from providing adequate fuel supply which is why it would run slowly for longer that full throttle.
At this point I made a mistake by over tightening the bowl bolt. Pulled the full bowl under the carb and cleaned it up then reinstalled. Drained the tank and flushed it out with fresh gas. First, a fouled spark plug caused by bad gas. Going to full choke, I could get the engine to run but it really ran rough. When bringing the throttle down to its minimum rpm, the engine ran longer but eventually it died. It wouldn’t start easily and would shut down fairly quickly at full throttle.
I got my rototiller out of storage to do some yard work. Low fuel pressure can cause this level of performance. You performed routine maintenance on the engine and the best you can get is a very low rpm. Engine was starting, running and shutting down normally. My thought on this concerns your chain of events. There’s several ideas for troubleshooting your problem.
