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Chain will stop with very little resistance.
I have this problem already mentioned.
Anybody have a solution? Seems to be a slipping clutch but electric seems to be direct drive with no clutch. Throw it away??

the ES300 is not a direct drive. It uses a bras or steel pinion gear, and a nylon drive gear. The nylon drive gear is bonded to a steel shaft at the time of fabrication.

If you can hold the chain sprocket and rotate the drive gear on the shaft by hand, it needs to be replaced. This test requires some dis-assembly, but you'll need to do that to replace it anyway.

I have included a link to an online store that includes an exploded view of the ES300.