Have changed fuel lines, filter, pump and 02 sensor after a day sensor covered in black crud yet again and running rough. Im guessing its a computer problem telling it to dump fuel or make a lean mixture. would appreciate any advise or what to try next ,hate to take to dealer way too expensive plus even if I had just serviced it they change oil and charge me really tics me off lol:
Not yet changed o2 sensor bought a new exmark navigator because I take care of 50 plus customers mainly just use walker for scalping and leaf clean up since having the issues really frustrating. I have read it could be the engine oil pressure sensor or engine speed sensor but would really like to narrow it down please help if anyone has an idea.
From a service bulletin I was reading, It could be a bad main harness ground. Make sure the harness ground is connected to the starter bolt, and has a copper connector not the stainless steel connector. Also rich running has been linked to a crack in the muffler, bad grounding of the O2 sensor through the muffler, and wear at the throttle position sensor.
That year of EFI also had issues with water getting into the ECU and well as the oil temperature sensor.
