Tecumseh OHV125 backfires

[bwestbrook]

Tecumseh OHV125 203039B had no spark so I replaced coil. Runs now but surges and backfires. Occasionally while it is running a spark or two would come out from under the flywheel it seemed. Adjusted valves. Cleaned carb. Flywheel key looked fine but did not take flywheel off just the nut. What else could I look for?

 

[ILENGINE]

The surging and backfire could be due to dirt in the carb. I would start by cleaning the carb. the sparking under the flywheel could be indication of a alternator stator shorting out and should pull the flywheel to look.