[quote=&quot;admin&quot;:c0mcm2cz]I overlooked the obvious. Check the chain coupler for alignment and for wear in the chain. With the tractor off, I reach in there and feel the sprocket teeth on the sides and top to make sure they are even. If the chain is worn, it can be replaced without pulling the motor.[/quote:c0mcm2cz]

Yup, had the same thing on our 1855, changed the chain coupler and that solved it.