Possible failing motor?

[Bravofox]

After a flight this morning, I detach the props to store the P4 in my case and I then noticed this on one of the motors:

To me it looks like burn/smoke markings. Anyone else ever came accross this?
It did not smell like it was burnt and the motor was not hot to the touch at all.
I have never had a crash or any incident that interfered with propeller movement. I also almost never use Sport mode as I feel it stresses the motors too much.

 

[With The Birds]

I think we are looking at dirt. Have a look at the fans in your computer, or anywhere you get high airflow.

 

[Steve7777]

If you've already put your nose close to the motor and there's no smell of burning and it wasn't overly hot, then it's probably OK. As With The Birds has said, it's possibly just dirt.

 

[wa5tef]

Does the prop on that motor spin freely and slow down at the same time when shutdown?
Good luck
Jim
WA5TEF

 

[N017RW]

After a flight this morning, I detach the props to store the P4 in my case and I then noticed this on one of the motors:View attachment 94704
To me it looks like burn/smoke markings. Anyone else ever came accross this?
It did not smell like it was burnt and the motor was not hot to the touch at all.
I have never had a crash or any incident that interfered with propeller movement. I also almost never use Sport mode as I feel it stresses the motors too much.

It appears to be metal 'dust'/powder from where the prop mount spring rubs against the outrunner. Notice it's only appearing in those areas where there is contact. Since the outrunner is aluminum and softer than the spring (steel) it is likely aluminum oxide which is consistent with the color.

This is not indicative of any type of motor failure. Don't panic as failure is not imminent or likely. You can remove the spring and clean as often as you feel comfortable with.

 

[Bravofox]

It appears to be metal 'dust'/powder from where the prop mount spring rubs against the outrunner. Notice it's only appearing in those areas where there is contact. Since the outrunner is aluminum and softer than the spring (steel) it is likely aluminum oxide which is consistent with the color.

This is not indicative of any type of motor failure. Don't panic as failure is not imminent or likely. You can remove the spring and clean as often as you feel comfortable with.

Thanks for that! Yes, my bird is in need of a good cleaning. It catches quite some bugs.