I have small Troy_bilt tiller. The engine runs and the tines turn when its running and not in the dirt. When in the dirt the tines immediately slow down and stop. The engine also bogs down when this happens. I've taken the transmission apart and cleaned and greased it and I also adjusted the valves to the fact specs. After preforming these 2 steps the results have been the same. Can anyone make a suggestion as to what to look for next.
If you've checked everything mechanical, maybe it's as simple as replacing the diaphragm. I've had these "go bad" due to the ethanol in the gas and the symptoms are a variety of 'not running correctly'.
It's a very cheap fix and only takes a few minutes to replace. It has made a BIG difference in all of the times I've put a new one in.
Please let us know how you make out in your troubleshooting.
Just as a side note: I have an old rototiller that wouldn't run right and finally wouldn't start. Problem was a bad condenser. Runs like new now. (Newer models have electronic ignition, as you may already know.)