Did you get any diagnostic lights this time?
I'd clean that vacuum hose one more time and re-seat the hose and make certain that the blower motor connections are also full seated.
If the problem continues then I'd just replace the blower motor.
The reason the motor doesn't rattle outside of the mount is because holding the motor stopped the rattle or what is rattling is where the motor mounts to the blower housing. This is one of several reasons why macman kept asking about the gasket.
I don't know what action your stove takes if it overheats other than stopping the pellet feed, hopefully it doesn't stop the combustion blower as well.
I'd clean that vacuum hose one more time and re-seat the hose and make certain that the blower motor connections are also full seated.
If the problem continues then I'd just replace the blower motor.
The reason the motor doesn't rattle outside of the mount is because holding the motor stopped the rattle or what is rattling is where the motor mounts to the blower housing. This is one of several reasons why macman kept asking about the gasket.
I don't know what action your stove takes if it overheats other than stopping the pellet feed, hopefully it doesn't stop the combustion blower as well.